Obsidian Aqua, catechol staining developer

[Jay DeFehr]

I'd like to introduce a new developer I've been testing for some time, and will continue to test and use. I call it Obsidian Aqua, for its scalpel-sharpness and water base.

Obsidian Aqua is very closely related to Hypercat II, but takes advantage of some of the opportunities an aqueous solution provides for economy, without sacrificing keeping prperties. The main reason for using propylene glycol in Hypercat II is to extend its keeping properties, but this comes at at some cost. PG is not locally available in many places, and is expensive to ship, and adds considerable expense to the developer. In Obsidian Aqua I've tried to maximize keeping properties while minimizing expense, including shipping costs, by utilizing locally available ingredients where possible, including the use of distilled water as the solvent. Like Hypercat II, OA uses catechol as its sole developing agent, but OA is preserved by metabisulfite in the stock solution, instead of ascorbic acid, and retains carbonate as the accelerator. OA can be made up in sodium or potassium metabisulfites and carbonates, depending on availability.

To maximize the keeping properties, the stock solution is highly concentrated. This allows for a higher ratio of catechol to metabisulfite, and a lower ratio of metabisulfite to water compared to other catechol staining developers, which simultaneously improves stain formation and keeping properties. A working solution of catechol/carbonate developer with appropriate carbonate content requires practically no preservative. The preservative is primarily required for the stock solution.

To make a working solution, the OA stock solution is dissolved into a solution of 6.66% carbonate, and how this is managed will depend on the carbonate used, and the preferences of the photographer. A 66.6% solution of potassium carbonate can be made by dissolving 666g of potassium carbonate to make 1 liter of stock solution, or 6.66g of either carbonate can be dissolved in a liter of water to make a working solution, or any number of other possibilities. The important thing is that the working developer contains 6.66g of carbonate/ liter.

Obsidian Aqua

Distilled water 700ml
Metabisulfite (sodium or potassium) 20g
Catechol 250g
Distilled water to 1 liter

Dilute 1:500 with 6.66% carbonate solution (sodium or potassium, depending on which metabisulfite is used in the OA stock solution). 1 liter of Obsidian Aqua makes 500 liters of working solution.

Develop TMY-2 12:00 @ 70F with *geometric agitation sequence.

Obsidian Aqua produces negatives of unsurpassed sharpness, excellent gradation, very fine grain, and full film speed. OA can be used with rotary processing, but with some loss of film speed. I hope this developer will be more convenient for my friends overseas, who often need to order supplies from outside their own countries. I highly recommend Artcraft Chemicals (http://www.artcraftchemicals.com/products/products-page/general-chemistry/a-m/catechol-part-1660/) for catechol. Artcraft offers 250g of catechol, which wouldn't require any weighing of the chemical to make up the stock solution; just mix the entire amount to make 1 liter. The metabisulfite is not critical, and could be measured with measuring spoons if no scale is available. 1 level teaspoon of metabisulfite weighs approximately 6.5g, so 3 tsp/ liter is close enough.

Obsidian Aqua stock solution should keep very well. Though I have no stock solution older than 6 months, I expect it to last at least a year in a partially full glass bottle. Time will tell.:)

I hope this formula is useful for anyone desiring the sharpest possible negatives with the best overall Image Quality, at the least possible expense, wherever one might live.


* The notion of a geometric agitation sequence was recently suggested to me, and I've been using it with good results. My method is as follows:

I use a count up timer, and begin by agitation continuously for 1 minute. Then I reset the timer and agitate for 10 seconds, according to the following progression (in minutes): 2, 4, 8, 16, 32, etc.

A geometric agitation sequence seems appropriate for this kind of very dilute developer, and my results bear this out.

[John Kasaian]

PG does a splendid job of keeping Prince Albert pipe tobacco fresh! Such a good job that the Prince moved out of his can and into a "Luxury Pouch."
This new developer sounds very interesting---I may have to give it a try. Thanks for sharing!

[Jay DeFehr]

The working solution is essentially the same as Hypercat II, which I've been using for quite a while, and some other photographers, too. Incredibly sharp! Good luck, and please don't hesitate to contact me with any questions or comments.

[Drew Wiley]

If it's as good as the name you picked for it, I'll have to try it! Maybe you should be
in marketing!

[gth]

If it's as good as the name you picked for it, I'll have to try it! Maybe you should be
in marketing!

Oh, man I can see it now....

Cue to OA Man, the rugged individual surveying his Bad Lands domain from the hilltop in profile against the far horizon, no shirt and ample sixpak, displaying the results of lugging a Deardorf through the hills for years.

He turns and takes a few steps towards the camera his flinty gaze burning through the f64 lens while the Badlands background fades to SHARP black and white. Slowly stroking his salt and pepper beard, he touches his Stetson in a gently greeting and says;

"Use Obsidian Aqua, for Acutance you can depend on."

/gth

[MIke Sherck]

Oh, man I can see it now....

Cue to OA Man, the rugged individual surveying his Bad Lands domain from the hilltop in profile against the far horizon, no shirt and ample sixpak, displaying the results of lugging a Deardorf through the hills for years.

He turns and takes a few steps towards the camera his flinty gaze burning through the f64 lens while the Badlands background fades to SHARP black and white. Slowly stroking his salt and pepper beard, he touches his Stetson in a gently greeting and says;

"Use Obsidian Aqua, for Acutance you can depend on."

/gth

Cue the soundtrack music from "The Good, The Bad, and The Ugly".

:) Mike

[Jay DeFehr]

Oh, man I can see it now....

Cue to OA Man, the rugged individual surveying his Bad Lands domain from the hilltop in profile against the far horizon, no shirt and ample sixpak, displaying the results of lugging a Deardorf through the hills for years.

He turns and takes a few steps towards the camera his flinty gaze burning through the f64 lens while the Badlands background fades to SHARP black and white. Slowly stroking his salt and pepper beard, he touches his Stetson in a gently greeting and says;

"Use Obsidian Aqua, for Acutance you can depend on."

/gth

:D I love it!

[John Jarosz]

Is the stain similar to Pyrocat and other staining developers? i.e, proportional to silver density?

Thanks

John

[evan clarke]

Excellent, I have 20 pounds of potassium carbonate lingering on the shelf and have all the other chems..I'll try this. Jay, how much loss of speed with rotary agitation? Could be a useful tool too..Evan Clarke

[Jay DeFehr]

John,

Yes, the stain is proportional, and the same brown-ish color as other catechol staining developers.

Evan,

In my tests, OA produces a speed increase of about 1/3-1/2 stop over box speed with Low Frequency Agitation, and rotary processing costs up to a full stop, or about 1/2-2/3 stop under box speed. Except for the speed loss, OA is excellent for rotary processing, producing no fog or general stain, and very even development with no streaking or mottling, but it really shines with Low Frequency Agitation, where it produces maximum acutance and compensating effects. But, if you can live with the speed loss, I think you'll be very happy with your results from rotary processing, too.

I'll try to post an example of OA with rotary processing.

[evan clarke]

John,

Yes, the stain is proportional, and the same brown-ish color as other catechol staining developers.

Evan,

In my tests, OA produces a speed increase of about 1/3-1/2 stop over box speed with Low Frequency Agitation, and rotary processing costs up to a full stop, or about 1/2-2/3 stop under box speed. Except for the speed loss, OA is excellent for rotary processing, producing no fog or general stain, and very even development with no streaking or mottling, but it really shines with Low Frequency Agitation, where it produces maximum acutance and compensating effects. But, if you can live with the speed loss, I think you'll be very happy with your results from rotary processing, too.
I'll try to post an example of OA with rotary processing.


Thanks, I rate 400 TMY at 320 when metering and Pyrocat MC is one of my developer choices, I always make at least two duplicate sheets. I'll make this tomorrow and compare this weekend..Thanks, Evan

[gth]

Anyone knows where you get catechol in Canada?

/gth

[Jay DeFehr]

Thanks, I rate 400 TMY at 320 when metering and Pyrocat MC is one of my developer choices, I always make at least two duplicate sheets. I'll make this tomorrow and compare this weekend..Thanks, Evan

Great! I look forward to your impressions.

[Vaughn]

Dang, Jay...you are about to drag me back to pyro...

[Jay DeFehr]

Dang, Jay...you are about to drag me back to pyro...

Vaughn, I think it's an ideal developer for your work, and your development method (trays, right?).

[gth]

Anyone knows where you get catechol in Canada?

/gth

Trying again!

[Jay DeFehr]

http://www.guidechem.com/products/120-80-9_country-Canada.html

Might be worth a try?

[ClaudioSz]

Jay, a little mistake.
"Dilute 1:500 with 6.66% carbonate solution (sodium or potassium, depending on which metabisulfite is used in the OA stock solution). 1 liter of Obsidian Aqua makes 500 liters of working solution. " You need a carbonate dilution with 6,66g in each liter (1000 ml), and this means 0,666% not 6,66%. This solution have a pH of 11,14.
I suppose when you mix with the catechol and metabisulfite of part A, the pH lower to around 11.
Claudio Szarfsztejn

[Jay DeFehr]

Jay, a little mistake.
"Dilute 1:500 with 6.66% carbonate solution (sodium or potassium, depending on which metabisulfite is used in the OA stock solution). 1 liter of Obsidian Aqua makes 500 liters of working solution. " You need a carbonate dilution with 6,66g in each liter (1000 ml), and this means 0,666% not 6,66%. This solution have a pH of 11,14.
I suppose when you mix with the catechol and metabisulfite of part A, the pH lower to around 11.
Claudio Szarfsztejn

Thanks for the correction, Claudio. Your pH calculation looks about right, too.

[cdholden]

Jay,
Your mention of "produces no fog or general stain" drives me to ask... would this developer be a better choice than others when using older films from the freezer that may have a growing density of base + fog as they age (i.e. Super-XX)?

Chris

[Jay DeFehr]

Hi Chris,

Yes, I think so, but there's some question as to whether a staining developer of any kind is the best choice for films with a lot of base fog. I suppose a staining developer can still provide a larger density range than a non-staining developer, important if one is printing in a long scale process, but staining the fog will definitely increase printing times, so it's a judgement call. But yes, if you are decided to use a staining developer, one that produces the minimum general stain is the best choice.

Catechol itself is quite resistant to fogging, which contributes to general stain. In catechol developers that produce fog/general stain, it is almost always the secondary developing agents responsible. This is why a catechol developer that also includes phenidone requires a restrainer. Phenidone, and even metol produce fog in a pH environment appropriate for a catechol developer, and provide no benefit to justify this fault. I don't think phenidone or metol are superadditive with catechol, and perhaps not even additive. If you compare developing times for standard dilutions of Obsidian Aqua and Pyrocat HD, for example, you'll see what I mean. Even though OA contains no phenidone, and uses a lower concentration of carbonate, development times for OA are typically shorter than development times for Pyrocat HD at comparable dilutions. How can this be? Well, I don't know, exactly. There's an awful lot of reactions taking place in a Pyrocat HD working solution that are not present in OA, and some must have a braking effect on development. The same is true for Tanol Speed, which contains both catechol, and pyrogallol, along with two other developing agents, and yet development times are longer than with OA, and fog/general stain are higher, too.

In my opinion, catechol developers are not improved by the addition of secondary/tertiary etc. developing agents, and all the other ingredients added to mediate their effects. Simply balancing the concentrations and ratios of catechol, preservative and alkali is all that is required to make a developer that does everything we want one to do, and nothing we want it not to do. All the rest is obfuscation and confusion.

[cdholden]

Thanks for sharing the formula for this developer. It looks inexpensive for such a large quantity, and the long shelf life is a great reason for me to conder its use. I've ordered some catechol and already have the others. I look forward to trying it in the near future.

[Jay DeFehr]

Chris, I'm always happy to share my work, and I hope others find it useful. OA is very inexpensive, and a little goes a long way. It can be a little tricky to measure out tiny volumes required for small tanks, due to the high concentration of the stock solution. A graduated pipette (http://www.astolab.com/pipette-graduated-234.html) can make things a lot easier, and the bulb type are accurate enough for photo work. The first time you measure out 0.6ml for 300ml of solution can be a little unnerving, but after a few times, you get used to it.

Feel free to contact me directly at:

jdefehr@gmail.com

with any questions or comments. Good luck!

[Jay DeFehr]

Any results from brush development in flat bottom trays?

Compared to Sandy King's Pyrocat HD, what would I expect to see that you would call an improvement - and viewable in the final print?

Brush development works very well with OA. Compared to Pyrocat HD, OA is sharper, finer grained, produces less fog/general stain, and more compensation with intermittent agitation.

[Michael Cienfuegos]

Chris, I'm always happy to share my work, and I hope others find it useful. OA is very inexpensive, and a little goes a long way. It can be a little tricky to measure out tiny volumes required for small tanks, due to the high concentration of the stock solution. A graduated pipette (http://www.astolab.com/pipette-graduated-234.html) can make things a lot easier, and the bulb type are accurate enough for photo work. The first time you measure out 0.6ml for 300ml of solution can be a little unnerving, but after a few times, you get used to it.

Feel free to contact me directly at:

jdefehr@gmail.com

with any questions or comments. Good luck!

A 1.0 cc syringe is graduated to 0.01 cc, so it should be accurate enough.

m

[Jay DeFehr]

A 1.0 cc syringe is graduated to 0.01 cc, so it should be accurate enough.

m

Yes, I use both. A syringe is more convenient for solutions in TEA or glycol, but a pipet is more convenient for aqueous solutions.

[Dan Henderson]

This sounds like an interesting developer. However, the terms "low frequency" and "intermittent" agitation have been used here and are confusing me. Jay, can you define these terms more precisely? I assume that they mean more frequent agitation than stand (agitation for only the first 1 or 1 1/2 minutes after the developer is added) or semi stand (initial agitation plus one agitation cycle halfway through development.) Thank you in advance for the clarification, and for sharing your research.

[Jay DeFehr]

Hi Dan. I think you have the gist of it. Agitation frequency ranges from continuous at the high end, to stand at the low end, with a range of frequency in between. I consider "normal" agitation frequency to be the Kodak standard of 5 seconds every 30 seconds, or Ilford's standard of 10 seconds every minute, though this standard should not be thought of as the mean or median between the extremes. Low Frequency Agitation would be below these standards, and High Frequency Agitation above. Gordon Hutching's recommended agitation frequency of 5 seconds every 15 seconds would qualify as High frequency agitation, and all the various schemes such as semi-stand, minimal, extreme minimal, etc., would qualify as Low Frequency Agitation, meaning less frequent than standard.

Agitation frequency can be visualized as a wave form, with rest periods alternating with agitation periods, and the amplitude of the wave as the vigor of the agitation. If, for example, we take an agitation scheme of continuous gentle inversions for 30 seconds, followed by 1 gentle inversion every 3 minutes, we could visualize this as a low frequency, low amplitude wave, and might be appropriate for a dilute developer and a high contrast scene. Another scheme might be to vigorously shake the tank for 30 seconds, and then to repeat for 5 seconds every 15 seconds, and we could visualize this as a high frequency, high amplitude wave that is typical for Technidol and Technical Pan development.

This is probably more than you care to think about agitation, and to some extent it's more theoretical than practical, but there is a practical basis with a developer like Obsidian Aqua that is more sensitive to agitation than general purpose developers are. Visualizing agitation as a wave form with both frequency and amplitude has helped me to theorize about agitation schemes, and to test my theories, but it might be of little or no interest to anyone else. I hope I've answered your questions without putting you to sleep!

[Dan Henderson]

I was hoping this thread would continue on as I am very interested in mixing up and trying a batch. So I will provide a bit of agitation...

Jay: thank you very much for your detailed reply. After reading it and rereading the entire thread, I am assuming that you recommend the "geometric" agitation plan that you discussed in your original post? With that agitation, where do you suggest I begin for an N development time with Ilford HP4 Plus?

Anyone else: have you tried this yet and what are your impressions?

[Dan Henderson]

I was hoping this thread would continue on as I am very interested in mixing up and trying a batch. So I will provide a bit of agitation...

Jay: thank you very much for your detailed reply. After reading it and rereading the entire thread, I am assuming that you recommend the "geometric" agitation plan that you discussed in your original post? With that agitation, where do you suggest I begin for an N development time with Ilford HP4 Plus?

Anyone else: have you tried this yet and what are your impressions?

[Jay DeFehr]

Hi Dan,

I'm experimenting with the geometric agitation scheme, but I'm not sure I can recommend it as having any practical advantage over more typical schemes. I'm not sure whether you mean FP4+, or HP5+.

For FP4+, try OA 1:500, 9:00, 70F, with a geo sequence of 30 seconds initial agitation followed by 10 seconds at 2:00, 4:00, 8:00, or a more standard sequence of 2:00, 4:00, 6:00.

For HP5+, try OA 1:500, 15:00, 70F, with a geo sequence of 30 seconds initial agitation followed by 10 seconds at 3:00, 6:00, 12:00, or a more standard sequence of 3:00, 6:00, 9:00, 12:00.

These are WAGs based on my experience with other films, and not on testing these films, so don't commit important films to these recommendations. Optimum development produces a negative with a density range suitable for the printing process, so one must know the exposure scale of the printing process, and the brightness range of the scene to determine best exposure and appropriate development. My WAGs should give you a printable image upon which to base further adjustments to exposure, development, and agitation. Be aware these low frequency agitation schemes will produce pronounced edge effects that might not be suitable for all images.

If you're wary of making up a liter of OA (quite a commitment), you can make 100ml:

Distilled water 70ml
Metabisulfite (sodium or potassium) 2g
Catechol 25g
Distilled water to 100ml


This will make 50 liters of 1:500 working solution, which should be enough to give you a good feel for its characteristics and working properties.

Good luck, and feel free to contact me with any questions or comments, here, or directly at:

jdefehr@gmail.com

[Dan Henderson]

Jay: thank you for suffering a fool; I meant to write FP4+.

I appreciate the starting development times; and I do plan to just expose a few sheets on something mundane near my home for testing, I also was thinking of making up a small batch to play with.

[IanG]

Is this not just a very minor variation on pre-WWII Pyrocatechin developers ?

Ian

[Jay DeFehr]

Dan,

If that makes you a fool, I'm a founding member of that club! Good luck!

Ian,

There are many, many developers based on catechol; some use carbonates while others use hydroxides, some are staining developers, some are not, some are 2-bath developers, and all are variations on the same theme; that theme being catechol as the sole developing agent. Catechol staining developers that include a secondary, or multiple developing agents is a new theme of dubious value.

Whether my variation is major or minor (or very minor) depends on your criteria. Differences among developers that share common ingredients might appear to be minor, but the effects of varying proportions and concentrations can be dramatic. Catechol + hydroxide + KBr can be used to make a very effective lith print developer, or an equally effective compensating film developer by just such variations.

Pre-WWII films were much different than the films we use today, especially the newest technology films, like TMY-2 and Acros, etc. One might be able to take a pre-WWII catechol/carbonate film developer and adjust dilution alone to give acceptable results with modern films, but that seems a pointless limitation. These kinds of developers are so simple, it just makes more sense (to me) to start with a set of design goals and try to achieve them in the most direct way possible. This is what I've done with Obsidian Aqua, and it should come as no surprise to anyone that OA bears a family resemblance to other developers of its kind.

Some differences:

OA is the most concentrated developer of its kind. This strategy achieves two design objectives: improved keeping properties, and improved image stain. Increasing the concentration of the stock allowed me to increase the ratio of developing agent to preservative in the working solution for improved staining, while simultaneously decreasing the ratio of preservative to total solution volume in the stock, for improved keeping.

OA uses a lower concentration of carbonate than other developers of its kind. Modern films don't require the high carbonate developers pre-WWII films did, so OA works at a pH 10X or more, lower than pre-WWII developers, and requires no restrainer.

OA working solution is more dilute than other developers of its kind. Pre-WWII developers typically used 2 or more grams of catechol per liter of working solution, while OA uses 0.5g per liter. A more dilute solution is more prone to local exhaustion during development, and the edge and compensating effects that result from local exhaustion. This in turn increases the appearance of sharpness in the negative and the print.

Taken together, the above combine to form a very different developer. One couldn't make a pre-WWII developer perform like OA without adjusting it to become OA.

[Lachlan 717]

OA uses a lower concentration of carbonate than other developers of its kind. Modern films don't require the high carbonate developers pre-WWII films did, so OA works at a pH 10X or more, lower than pre-WWII developers, and requires no restrainer.


Thanks for this thread, Jay.

How do you think OA will go with the more traditional/old style films, such as Adox/Efke?

[Jay DeFehr]

Hi Lachlan,

Even our "old style" films are very modern compared to pre-WWII stuff, and OA will work very well with them. Ilford PF+ is a fairly "old-style" film, and one of my favorites with OA. Foma films look great, too. I'll try some of the Efke/Adox stuff when I get home, but I'm very confident it will look great. These films benefit from a tanning/hardening developer like OA, and can be extremely sharp. OA is cheap-- give it a go!

[Lachlan 717]

Hi Lachlan,

Even our "old style" films are very modern compared to pre-WWII stuff, and OA will work very well with them. Ilford PF+ is a fairly "old-style" film, and one of my favorites with OA. Foma films look great, too. I'll try some of the Efke/Adox stuff when I get home, but I'm very confident it will look great. These films benefit from a tanning/hardening developer like OA, and can be extremely sharp. OA is cheap-- give it a go!

Thank again, Jay.

This seems to be a set of chemicals easily (although not initially cheaply) available in Australia (the Catechol if $65 for 100g!!). However, with the dilutions you recommend, this will amotise into a very cheap brew quite quickly.

So much easier to do this that wait for PF to send through some of their Pyro kits...

[Jay DeFehr]

Thank again, Jay.

This seems to be a set of chemicals easily (although not initially cheaply) available in Australia (the Catechol if $65 for 100g!!). However, with the dilutions you recommend, this will amotise into a very cheap brew quite quickly.

So much easier to do this that wait for PF to send through some of their Pyro kits...

Lachlan,

I had no idea catechol is so expensive in Australia. It seems it would be cheaper to order it in from Artcraft at US$26.00/ 250g + shipping. This is a major motivation for this formula. Metabisulfite, carbonate and water are available almost everywhere, and a little catechol goes a long way, so shipping catechol alone shouldn't be prohibitive. I hope you can find a better deal on your catechol. Good luck, and let me know if I can be of any help.

[Cor]

Jay,

Could you give a starting point for Ilford PanF, expose box speed I guess, but process for how long at what temperature?

Thanks,

Cor

[John Bowen]

Very interesting...
Thanks for sharing Jay

[Jay DeFehr]

Jay,

Could you give a starting point for Ilford PanF, expose box speed I guess, but process for how long at what temperature?

Thanks,

Cor

Hi Cor,

OA and PF+ is one of my favorite combinations. A good starting point is:

OA 1:500, 70F, 8:00, agitate first 30 seconds, and then ten seconds/ minute.

The above should provide a point of departure for your own testing.

John,

I'm happy to share my work with other photographers, and I hope you find something useful in it.

[Cor]

Thanks Jay!

I'll report back (although it will be 35mm...:)..)), I just have to wait for sufficient light outside right now,

Best,

Cor

[Jay DeFehr]

Hi Cor,

If you shoot in flat light, you might want to increase development a little. I think you'll like this combination.

[Andrew O'Neill]

Anyone knows where you get catechol in Canada?

/gth

You can get catechol from Nymoc in Toronto. Email John Burrows: nymoc@bellnet.ca

[Dan Henderson]

I finally got caught up on some other pressing projects and had time to shoot a scene on which to test Obsidian Aqua developer, and offer the following comments:

1. The "A" portion of the developer was easy to mix, metabisulfite and catechol in distilled water. Rather than make a stock "B" solution, I added enough sodium sulfite to water to make a 6.66% working solution into which I added the 1:500 dilution of developer.

2. Following Jay's recommendation I developed 4x5 FP4+ for 9 minutes at 70 F. I agitated for the first 30 seconds, then 10 seconds every 2 minutes.

3. I got a nice, easily printable negative. Good contrast, same stain as I am accustomed to with Pyrocat.

4. To attempt to ascertain any difference in sharpness, I made an enlargement of a section of the negative with lots of detail at the highest magnification my setup will allow (actually as large as my anatomy will allow; with my eye to the focus finder I could just barely reach up to the focusing knob.) It is roughly equivalent to a 20x24" enlargement.

5. I compared this enlargement to an identical enlargement of another negative of the same film, exposed at the same time, but developed in Pyrocat HD, using semi-stand agitation. Using a strong magnifier, I "think" the O.A. enlargement is nominally sharper. I intended to scan and post the enlargements but they are so close that I am sure any differences would not survive the scanning and uploading process. At any rate, I feel comfortable stating that the O.A. enlargement is no worse than equally as sharp as the Pyrocat enlargement, even with more aggresive agitation.

6. As sharp as this negative is, I wonder if it could be improved with a less aggressive agitation routine, such as 30 seconds initial agitation followed by 10 seconds of agitation at the 1/4, 1/2 and 3/4 points, or even 1/3 and 2/3. I intend to explore this idea in the near future.

Thanks again to Jay for providing this developer, and for his generosity in sharing it here.

[MDR]

Thank you Jay for providing once again an alternative developer. Have to try it as soon as I can get all the ingredients. Btw have you noticed that your stated amount of carbonate is the number of the beast 666 maybe that's why your developer works so well :-)

Dominik

[gth]

Jay,

1. What is the shelf life of the Catechol compound by itself? Reason I ask because in Canada it needs to be shipped as a dangerous compound so I might as well get a fair amount while I am at it. In other words several years worth.

2. How much diluted solution is needed to develop a specific amount of film - as in film area per liter? Normailized to How many rolls 35 or 120 per liter or how many 4x5 sheets per liter etc. This estimate to be taken conservatively.... i.e assuming I would be fairly frivolous with its use - one shot type....

3. Also... has anyone used OA on X-ray film emulsions?

/gth

[mat4226]

3. Also... has anyone used OA on X-ray film emulsions?



73238

I've used OA with quite a few sheets of X-ray film now, and all I have to say is I'm in love! With that interval agitation Jay talks about on the first page, 1,2,4,8, etc., I'm able to shoot Green Latitude X-ray film @ ASA 320. This is, of course, considering I'm not stripping the emulsion, scanning and contact printing works fine. Here's a link to all the images I've already shot with OA as the developer, including 4 infrared shots as well (also great with OA!).

http://www.flickr.com/photos/mat4226/tags/oa/

[UlbabraB]

3. Also... has anyone used OA on X-ray film emulsions?
/gth

I plan to test it soon with Kodak T-Mat Green Xray film, Mat Marrash (IIRC he is a LFF member too) already did it, check his flickr stream: http://flic.kr/p/bzD9iU

[Max Hao]

Thanks for the correction, Claudio. Your pH calculation looks about right, too.

So, is it 0.666% sodium carbonate solution or 6.66%? How many grams of sodium carbonate in 1000ml water? Thanks.

[ClaudioSz]

Exactly 6,66 g/l. That means 0,666%, expressed as g of carbonate in 1000 ml of solution.

[Jay DeFehr]

Hello guys,

I'm just back from Russia, and catching up on things. I'm glad to see some of you having success with this developer.

Dan - Thank you for the detailed review. I assume the sodium sulfite is an error and meant to be sodium carbonate:) That OA used with intermittent agitation is sharper than Pyrocat HD used with semi-stand agitation is jut what I have found, as well, and you're also right to expect even sharper results with decreased agitation frequency.

Dominik - when I was testing OA, I tested carbonate concentration ranging from about 3g/ liter of working solution up to about 20g/ liter, and everything in this range is useful. The 666 solution resulted from diluting a more concentrated stock solution, and is a kind of sweet spot between 5g/ liter and 7.5g/ liter -- lower concentrations of carbonate begin to impact film speed, and higher concentrations tend to increase contrast and grain, but nothing was signed in blood, so I think my immortal soul remains free and clear.;)

gth- I don't know the shelf life of catechol powder, but I suspect it's good for at least several years properly stored, as mine is that old and still working fine. I haven't tested OA for developing capacity, but I know 1ml of concentrate will safely develop 1 roll of film, or equivalent.

Matt - thanks for the info on processing X-ray and IR films. Your examples on Flickr look great!

[Dan Henderson]

I continue to have good results with this developer, until I apparently pushed my luck a bit too far. I began developing FP4+ for 9 minutes at 21c, agitating the first minute then every 2 minutes thereafter as recommended by Jay. Being a minimal agitation guy, I began reducing agitation to 2, then a single period after initial. Things went nicely until yesterday, when some negatives with a clear sky were mottled and uneven in that area. It seems that I have read that stand or semi stand can be unpredictable, which seems to be the case here. In a subsequent session I added back an additional agitation period with no apparent adverse impact on sharpness.

A couple of questions for Jay if he happens to stop in:
1. I use a Yankee tank that can hold up to 12 4x5 sheets, although unless I have been on a shooting trip I seldom process more than 3 or 4 sheets at once. The tank holds 1625 ml, which works out to 3.25 ml of the A solution for 1+500. Would this amount of developer be sufficient for up to 12 sheets if the need arose?

2. When I used Pyrocat I would sometimes re use the developer on another batch of film requiring a different development time, with the developer sitting in a graduate for only a few minutes before being re used. Can this be done with O.A.? Or is it pretty much done after one use? Cost is obviously not a factor, but I have adopted the philosophy of not needlessly putting chemicals down the drain since moving into a house with a septic system.

[Jay DeFehr]

Hi Dan,

I'm glad you're getting good results. Finding a sweet spot for agitation is an important part of getting the most out of this developer, and as you found, at frequencies high enough to prevent defects, there is little negative impact on sharpness.

On capacity- the 1:500 dilution is standard, and used to develop 35mm film in 300ml of solution, with 0.3ml of stock. Since 4ea 4x5 sheets = 1ea 36 exp 35mm film, 1ml of stock will develop at least 12 sheets of 4x5 film, so 3.25ml is more than safe.

I do not recommend re-using OA -- it might work, but it's just not worth risking. And I wouldn't worry about adding it to your septic tank, either -- catechol, carbonates and metabisulfites are all found in things we eat and drink, and, consequently, in our urine, in far greater amounts than you're likely to add by dumping this very dilute developer.

How about some example pics?

[Dan Henderson]

Jay: thanks for the additional info.
Here is the latest print I have made from an O.A. negative. I am just beginning a series on mountain churches of southwest Virginia and have 2 negatives I plan to print in the next few days that I will post as well.

76673

[Jay DeFehr]

Thanks for posting an example, Dan. It looks great! There's a very nice contrast between the sharp edged rocks and velvety water. Nice image color, too. I tend to prefer warm images. I look forward to seeing your churches!

[Bob Farr]

Hi Dan,

I'm glad you're getting good results. Finding a sweet spot for agitation is an important part of getting the most out of this developer, and as you found, at frequencies high enough to prevent defects, there is little negative impact on sharpness.

On capacity- the 1:500 dilution is standard, and used to develop 35mm film in 300ml of solution, with 0.3ml of stock. Since 4ea 4x5 sheets = 1ea 36 exp 35mm film, 1ml of stock will develop at least 12 sheets of 4x5 film, so 3.25ml is more than safe.

I do not recommend re-using OA -- it might work, but it's just not worth risking. And I wouldn't worry about adding it to your septic tank, either -- catechol, carbonates and metabisulfites are all found in things we eat and drink, and, consequently, in our urine, in far greater amounts than you're likely to add by dumping this very dilute developer.

How about some example pics?

Hi Jay,

If you are using 300ml of working solution for a roll of 35mm film, is 0.6ml of OA stock the correct amount instead of 0.3??

Bob

[Jay DeFehr]

Hi Jay,

If you are using 300ml of working solution for a roll of 35mm film, is 0.6ml of OA stock the correct amount instead of 0.3??

Bob


Yes, Bob, that's right, 300/500= 0.6-- thanks for the correction. 0.3ml is what I used for Tech Pan, and that's a 1:1000 dilution, but the capacity is still valid. I shouldn't try to work from memory, and actually do the math!

[Bob Farr]

Yes, Bob, that's right, 300/500= 0.6-- thanks for the correction. 0.3ml is what I used for Tech Pan, and that's a 1:1000 dilution, but the capacity is still valid. I shouldn't try to work from memory, and actually do the math!

Hi Jay,

Thanks for your reply!! So, if 0.6ml of stock is needed for one roll of 35mm film and to develop four sheets of 4x5 film. Then it seems that at least 2.4ml would be needed for twelve sheets of 4x5. It's important because I wish to have an adequate volume of OA for 5x7 and 5x12 film.

Thanks,
Bob

[Jay DeFehr]

Hi Bob,

0.6ml is safe, but we can't say it's needed, because I developed a roll of 35mm film in 0.3ml (Tech Pan).

http://farm9.staticflickr.com/8161/7476329830_07976d6f6e_b.jpg (http://www.flickr.com/photos/jay_defehr/7476329830/) photo.JPG (http://www.flickr.com/photos/jay_defehr/7476329830/) by Jay DeFehr (http://www.flickr.com/people/jay_defehr/), on Flickr


For easy math, you can figure 0.5ml/ 8x10 or equivalent is a safe minimum.

[Bob Farr]

Yes, Bob, that's right, 300/500= 0.6-- thanks for the correction. 0.3ml is what I used for Tech Pan, and that's a 1:1000 dilution, but the capacity is still valid. I shouldn't try to work from memory, and actually do the math!

Hi Jay,

Thanks for your reply!! So, if 0.6ml of stock is needed for one roll of 35mm film and to develop four sheets of 4x5 film. Then it seems that at least 2.4ml would be needed for twelve sheets of 4x5. It's important because I wish to have an adequate volume of OA for 5x7 and 5x12 film.

Thanks,
Bob

[Bob Farr]

Thanks Jay

[Bob Farr]

Hi Jay,

The working solution is 1;500ml, so I'll need to mix up liters if not gallons of part B [666gms of carbonate per liter] for a developing session??

Bob

[Jay DeFehr]

Hi Bob,

The working solution contains 6.66g/liter of potassium carbonate, or 5g/liter of sodium carbonate. Mix up only as much working solution as you need. For each liter of working solution, use 2ml of OA stock + carbonate as described above.

You can make a stock solution of carbonate, and for this potassium is more simple and direct than sodium carbonate, because it's more soluble.

Potassium carbonate stock solution:

Water 700ml
Potassium carbonate 666g
Water to 1 liter

Use 1ml of the above for every 100ml of working solution.

Sodium carbonate stock solution:

Water 700ml
Sodium carbonate 200g
Water to 1 liter

Use 2.5ml of the above for every 100ml of working solution

[Bob Farr]

Hi Jay,

This helps a lot to understand how to use OA. To recap-

If using sodium metabisulfite for part A then 200gms of sodium carbonate in part B resulting in a 1:2.5:100 dilution.

Does this fit with the original dilution of 1:500?? Or should the working solution be 0.1:2.5:100??

Or if using potassium metabisulfite for part A the 666gms of potassium carbonate for part B resulting in a1:1:100 dilution.

Does this seem about right??

Bob

[Jay DeFehr]

Hi Bob,

I'm afraid that's not quite right. The compound ratios would be:

OA + potassium carbonate 66.6% + water = 1 + 5 + 500

OA + sodium carbonate 20% + water = 1 + 12.5 + 500

To mix with 100 parts water, you'd need to divide everything above by 5, as in:


OA + potassium carbonate 66.6% + water = 0.2 + 1 + 100

OA + sodium carbonate 20% + water = 0.2 + 2.5 + 100


The above makes for easy calculation, as the numbers are all multiplied by the desired final solution volume in 100s of ml. For example:

To make 300ml solution

With potassium carbonate 66.6%, (0.2 + 1 + 100) X 3 = 0.6 + 3 + 300

With sodium carbonate 20%, (0.2 + 2.5 + 100) X 3 = 0.6 + 7.5 + 300

Make sense?

[Bob Farr]

Thanks jay,

Am glad that all of this is getting cleared up before I jump into this.

Bob

[Jay DeFehr]

No problem, Bob. There are a lot of numbers involved, and it can be confusing, but once you decide on a working method, you can forget about a lot of the numbers, and concentrate on your personal process. I use potassium metabisulfite in my OA stock, and a 66.6% potassium carbonate stock solution. It's easy for me to remember that I use a 1:100 dilution of my carbonate stock solution to make a working solution, and I always make the alkali solution first. Then I simply add 0.2ml OA stock/ 100ml of the alkali solution to make a working developer. But, just in case, I labelled my carbonate solution 1:100, and my OA stock 0.2:100. I also ignore the tiny error in beginning with the desired final solution volume of water. So, if I'm making up 500ml of developer, I start with 500ml of water, add 5ml of carbonate solution and stir well, and then 1ml of OA stock, and stir again. I end up with 506ml of solution, but this has no measurable effect on results.

Once you do this a few times, you stop thinking about it -- it's just automatic-- very quick and easy.

I always use the same 1:500 dilution of developer (except when developing document films), and control edge effects with agitation. Most films I've tested develop in 12:00, 70F, with agitation at 3:00 intervals, to produce good prints on G2-3 paper. These films include: Kodak TMY-2, Fuji Acros, Adox CHS 50, and 25, Ilford Pan F+, and Foma 100. Some films, Like Foma 400, require 15:00.

Good luck!

[John Fink Jr.]

Sounds excellent Jay, thank you!!

[Jay DeFehr]

Hi John,

I'm very happy with this developer. If you decide to give it a try, and have any questions, don't hesitate to contact me--

jdefehr@gmail.com

[John Fink Jr.]

Thank you Jim, count on it:-)

[mikoyan]

Hello
First try with OA :)
Ilford Hp5+ 120 @200, Rolleiflex
Presoak 4 min
OA 1+500 9'30@25°C, 20 sec. agitation at beginning, and then 3 inversion at 7', 4'30 and 2'.
Water bath stop
Fix with RXN 1+7 4 min
Washing during 20 minutes, in order to remove a slight magenta cast
4 min in distilled water + Ilfotol
The film is drying now, it looks very good !

[coisasdavida]

Not sure if anyone asked this before, but here it goes:
Cookbook says generally bisulfite may substitute metabisulfite. Cookbook also says bisulfite is used as a preservative in pyro developers.
Jay, can bisulfite be substituted for the metabisulfite you list in your formula?
Thanks, Gui

[mikoyan]

Very good dev for Delta 100, Hp5+, TMY-2, Acros 100, Rollei Retro 80S, Foma 400 :)

[Andrew O'Neill]

Canadians looking for chemicals, try Nymoc in Toronto. That's where I get mine. Email John Burrows at nymoc@bellnet.ca.

[Jody_S]

Canadians looking for chemicals, try Nymoc in Toronto. That's where I get mine. Email John Burrows at nymoc@bellnet.ca.

Thanks. Never heard of them, I just sent a message. I was having trouble getting alkaline fixer shipped to Canada (without paying $40 for shipping).

[mikoyan]

And good result with PanF+ and FP4+.
OK, i had a lot of exposed rolls waiting in the fridge :D

[Jan Pedersen]

Bringing back this thread as I became interested in trying this developer and have some difficulties getting it to work.

After checking what I had of chems already I mixed up 250ml of part A as I had enough Catechol for that.
I first tried with Sodium Carbonate but could have used Pot Carbonate as I had both.
The problem I have are extremely thin negatives, I have developed Pan-F and TMY both in 120 format and I can't get anywhere near box speed as I read should be possible with reduced agitation.
With TMY I get no more than Iso 100

Today I mixed up a new B solution from Pot. Carbonate but it did not change a thing.

Is it possible that my Catechol was to old? it was stored for a few years, maybe 4 but still looked normal or I should say looked like it did when I purchased it.

I used Pyrocat MC for a few years so I know what the negatives should look like but with OA there's just no similarity.
Any idea what could be the problem?
Thanks.

[Regular Rod]

Bringing back this thread as I became interested in trying this developer and have some difficulties getting it to work.

After checking what I had of chems already I mixed up 250ml of part A as I had enough Catechol for that.
I first tried with Sodium Carbonate but could have used Pot Carbonate as I had both.
The problem I have are extremely thin negatives, I have developed Pan-F and TMY both in 120 format and I can't get anywhere near box speed as I read should be possible with reduced agitation.
With TMY I get no more than Iso 100

Today I mixed up a new B solution from Pot. Carbonate but it did not change a thing.

Is it possible that my Catechol was to old? it was stored for a few years, maybe 4 but still looked normal or I should say looked like it did when I purchased it.

I used Pyrocat MC for a few years so I know what the negatives should look like but with OA there's just no similarity.
Any idea what could be the problem?
Thanks.

I don't think dry Catechol goes off if sealed in a jar. In fact I believe that is one of the characteristics that Jay took into consideration when he was devising OA to last indefinitely.

Did you use Sodium Metabisulphite in your solution A? I think we are supposed to use Sodium Carbonate in Solution B if we use Sodium Metabisulphite and if we use Potassium Metabisulphite in solution A we should use Potassium Carbonate in solution B

Here's how I make up mine after Jay explained to me how I could save on the quantities of distilled water needed:

OBSIDIAN AQUA

Solution A
Distilled Water - 300 ml
Sodium Metabisulphite - 8 g
Catechol - 100 g
Distilled Water to make - 400 ml

Solution B (Concentrate)
Distilled Water - 4 litres
Sodium Carbonate Anhydrous - 1 kilo
Distilled Water to make - 5 litres

Working Solution
Solution A - 1 ml
Solution B - 12.5 ml
Tap Water to make - 500 ml

Try 12 minutes @ 20 degrees C semi-stand to start with. That is 60 seconds gentle agitation followed by 10 seconds gentle agitation every two minutes. A pre-soak in water at 20 degrees C seems to ensure even development quite nicely.


RR

[Jan Pedersen]

Yes, mixed just like that with Sodium metabisulphite. 6 gram for 75 gram of Catechol.
I ordered some fresh Catechol from Artcraft yesterday so will see if that impoves things when i get it.

Thanks for your reply.

[Regular Rod]

Hi Jan

How long are you developing for at what temperature?

RR

[Jan Pedersen]

TMY @ Iso 200 12 minutes at 22C. I can barely see the TMY in the film rebate so something is surely not working here.

[Regular Rod]

Hmmm.. That must be wrong somewhere...? We will have to wait until your new Catechol arrives!

;)
RR

[Andrew O'Neill]

I ran out of pyrocat-hd, which has been my standard developer for about 12 years, so I decided to give OA a shot. I have to say that this very simple developer is excellent. Very sharp, with a gain of a third stop in speed. Very smooth tones, less grain than pyrocat-hd. I appreciate the fact that only three chemicals are required. Looks like I'll be playing around with this developer for a while. Thanks Jay!

[Regular Rod]

I ran out of pyrocat-hd, which has been my standard developer for about 12 years, so I decided to give OA a shot. I have to say that this very simple developer is excellent. Very sharp, with a gain of a third stop in speed. Very smooth tones, less grain than pyrocat-hd. I appreciate the fact that only three chemicals are required. Looks like I'll be playing around with this developer for a while. Thanks Jay!


Echo that!

RR

[mikoyan]

Yes, OA is excellent :)

[Ken Lee]

Very smooth tones, less grain than pyrocat-hd. I appreciate the fact that only three chemicals are required.

Simplicity is good :)

Can you give us an estimate at how much less grain you see - a bit less, a lot less ?

Which film you are evaluating ?

What is a good way to accurately measure 1 ml ?

[Regular Rod]

For 1ml a pipette is best. (http://www.amazon.com/Mohrs-Pipette-Pipet-Borosilicate-Glass/dp/B007CL88SG/ref=sr_1_4?s=industrial&ie=UTF8&qid=1341534806&sr=1-4&keywords=pipet+1ml)

I have been getting away with very careful use of a 1ml syringe. The trick with the syringe is to check the base of the bubble in the syringe under the piston and use that as the mark to measure against the scale. The other important thing to remember if using a syringe is to make sure that last bit in the nozzle is NOT shaken out into the solution, that would take the volume over 1ml.

RR

[Andrew O'Neill]

Simplicity is good

Can you give us an estimate at how much less grain you see - a bit less, a lot less ?

Which film you are evaluating ?

What is a good way to accurately measure 1 ml ?

Hi Ken, as far as grain goes it was noticeably less grainy. I'll have to post a couple of scans.
Film used was FP4 8x10.
I use a glass pippet. Apparently the units scribed are more accurate and drops are more consistent.

To mix I use 25ml of a 20% solution of Sodium Carbonate into 750ml tap water. Then add 5ml catechol developer. Top off with tap water to a litre. Developed in a tray for 15:00 at 21C. I agitated constantly for the first minutes, then 10sec every 3 minutes.

[Corran]

I keep trying to like Pyrocat but I just don't, except some very rare instances.

I'd like to try this. Is there anyway to buy this stuff mixed? I don't have the need or want to buy raw chemicals and compound my own stuff.

[Andrew O'Neill]

Side-by-side comparison. Taken from even toned area of each negative. They are pretty close. Closer than I first thought when I checked through a loupe. OA's grain seems to have a slight edge in sharpness to me. You be the judge.
Still, an intriguing developer that I'll keep playing around with.

[Kirk Gittings]

So the amount of grain looks similar but the OA is clearly sharper at least in these scans.

[Ken Lee]

Thanks for sharing those comparison shots.

The image on the right looks out of focus compared to the one on the left: does that mean that there is more grain or that it is clumpier or thicker ? How can grain be sharper or blurrier ? Would it be more revealing to compare images of a target with lines on it, or some other recognizable form like a letter ?

[Andrew O'Neill]

So the amount of grain looks similar but the OA is clearly sharper at least in these scans.

It would appear so, Kirk.
You are probably right, Ken. I'll rescan and use more useful areas for the comparison.

[Andrew O'Neill]

Here's more to chew on... Negative on the left was developed in Pyrocat-HD. To its right is the OA negative. Far right is a comparison. The building's sign on the right-hand side was used. To my eye, the edges of the letter and line are not as fuzzy in the OA negative. They are pretty close, though.

[Taija71A]

Here's more to chew on... Negative on the left was developed in Pyrocat-HD. To its right is the OA negative. Far right is a comparison. The building's sign on the right-hand side was used. To my eye, the edges of the letter and line are not as fuzzy in the OA negative. They are pretty close, though.

____

WOW!!!
Outstanding comparison Andrew! :)
--
Thank-you, for taking the time to do this personal Film Developer 'comparison' Testing... And for posting it here on the forum -- For the benefit of all others. :D

Greatly Appreciated!
--
Best Regards,

-Tim.
________

[Jan Pedersen]

Andrew, I am curious about your exposure time when printing?
With my enlarger lens stopped down 2 stops which I find is the best performance I am looking at about 3 seconds maybe 4 and that is way to little for any work on the print.
I also find it difficult to believe that this developer is even close to develop any film close to box speed. I have rated TMY at 160 and the print exposure time is still way to short.
Curious to hear about your experience printing these negatives.

[lbenac]

Hello Andrew,
The same old question. In BC/Canada where do you get the ingredients from?
Cheers,

Luc

[Ken Lee]

Here's more to chew on... Negative on the left was developed in Pyrocat-HD. To its right is the OA negative. Far right is a comparison. The building's sign on the right-hand side was used. To my eye, the edges of the letter and line are not as fuzzy in the OA negative. They are pretty close, though.

The OA negative has cleaner edges - very nice !

Could you tell us how much of an enlargement this is ? In other words, at what degree of enlargement do you find the difference becomes noticeable ?

[Kirk Gittings]

Could you tell us how much of an enlargement this is ? In other words, at what degree of enlargement do you find the difference becomes noticeable ?

Good question Ken

[Andrew O'Neill]

Jan, I haven't printed this negative. I exposed it EI 64, but after measuring with a densitometre, I probably could have exposed at 80.
Hi Luc, I get my chemicals from Nymoc in Toronto. Email John Burrows: nymoc@bellnet.ca

Ken, I marked the negative area that was enlarged. As you can see, it would have to be enlarged quite a bit before you can really see a difference.

[StoneNYC]

ALMOST bit the buklet to buy some Catechol while ordering some CD-3 from Artcraft, but in the end I decided I have so many B&W developers I should run through those first before going crazy on something new.

But it brought a question, since I've never used pyrocat HD or any other staining dev, as far as fine grain and pushing, I always use DD-X... So, how does it compare to DD-X?

[Andrew O'Neill]

For me, a pyrocat negative allows me to print the same negative in silver or alt processes (I've not printed an OA negative yet). High values seem to print softer tonally on VC papers than with a conventional developer. Staining developers are supposed to have smoother tones, less grain due to stain filling in the spaces between the grain. Most of my experience with conventional developers has been with Xtol, which I have heard, is similar to DD-X, no? If you want to try a staining developer, OA might be a good one to try, since it only requires three chemicals, and mixes quickly and easily.

Now I need to focus on this hockey game. Been multi-tasking most of the day between this thread, making a carbon print, and watching the Canucks and Sharks game.

[rcmartins]

Andrew,
Could the differences between the two films stem from a slightly different agitation during development? I am asking because I honestly don't know. I am not implying anything with the question.
raul

[Ken Lee]

Ken, I marked the negative area that was enlarged. As you can see, it would have to be enlarged quite a bit before you can really see a difference.

Presuming that the film is 4x5, and sizing the image to 3.75 inches tall, the detail section is around 3/64 of an inch. I'm guessing that the detail section is around 1/20 inch tall on the negative. To see the detail section at 1 inch tall, we'd need an enlargement factor of 20 x.

[Andrew O'Neill]

raul, agitation was exactly the same.

[dsphotog]

What fixer would be best with OA?

[Regular Rod]

I use Ilford Rapid Fixer after a 20 deg. C stop bath of water.

RR

[Andrew O'Neill]

I use Ilford Rapid Fixer after a 20 deg. C stop bath of water.

I use the same fixer.

[StoneNYC]

Please correct me if I'm wrong, because I really don't know that much about the chemistry and of things, but isn't the fixture that is used more dependent on the type of film that you're using then the developer itself?

[Regular Rod]

You are right. It's more important to ensure that the developer doesn't get into the fixer too much. I think a pre-soak although not recommended by Ilford is still very well worth doing. I never had streaks or air bells since adding a pre-soak to my routine...

RR

[Andrew O'Neill]

I use one fixer for several films. I have heard that film that has been developed in a pyro or other staining developers, can reduce stain in some fixers... but I have no experience or even been a witness to it. I've used the same type of fixer for years, and have used 4 different staining developers, including PMK and ABC Pyro. I use a regular stop bath, containing either vinegar or citric acid. People who use TF4 fix are not required to use an acid stop bath. Plain old water is fine.

[Ken Lee]

I believe that a mild acid not only stops development quickly, but also helps prolong the life of acidic fixers.

If you use an alkaline fixer, you can still use a mild acid stop bath if you are concerned about arresting development immediately. Plain water will stop development, but more gradually. If you time your development down to the second, then a mild acid stop is not a bad idea, whatever fixer you use.

Citric acid is affordable and has no offensive odor.

[Regular Rod]

I stopped using acid stop baths when I used ADOX CHS Art Films, as ADOX recommended to use only water. The emulsions were delicate it would seem. Anyway it worked so well I thought I'd eschew acid stop baths for the other films I use and I have not found any reason to regret that. Consistency seems to be the key to success. Find out what suits yourselves and then stick to it. I'm sure the developer does carry on working for a few seconds after pouring out the developer and pouring in the water but as long as all this is the same each time you work then you will get consistent results. It's only when you change things that inconsistency can creep in. If your film and stop bath combination has worked for you then there is no need to change it because you have changed your developer. Particularly if it is a one-shot developer and not going to be re-used.

RR

[StoneNYC]

I stopped using acid stop baths when I used ADOX CHS Art Films, as ADOX recommended to use only water. The emulsions were delicate it would seem. Anyway it worked so well I thought I'd eschew acid stop baths for the other films I use and I have not found any reason to regret that. Consistency seems to be the key to success. Find out what suits yourselves and then stick to it. I'm sure the developer does carry on working for a few seconds after pouring out the developer and pouring in the water but as long as all this is the same each time you work then you will get consistent results. It's only when you change things that inconsistency can creep in. If your film and stop bath combination has worked for you then there is no need to change it because you have changed your developer. Particularly if it is a one-shot developer and not going to be re-used.

RR

Question, do you know how long the water needs to be there before the film fully stops developing?

Is it 10 seconds or 30 seconds or 2 minutes? With water I mean...

Ilford recommends 1 minute for ilfostop but I always rinse once or twice with water after the dev anyway so as to make the stop last longer without dev contamination. So, by the time the ilfostop gets to the film, have I already stopped it?

[Andrew O'Neill]

Question, do you know how long the water needs to be there before the film fully stops developing?


Film would need to be well soaked in a water bath/rinse with several changes of water so that none of the developer is carried over to the fix. I usually did several rinse/agitate/dump cycles for two minutes. I prefer an acid stop bath as it will extend the life of your fix.



So, by the time the ilfostop gets to the film, have I already stopped it?

Yes. It's pretty immediate. I remember using Ilfostop when I lived in Japan. It's mildly acidic (hence ILford's recommends a 1 minute bath) and less odour compared to their rapid fixer.

[Andrew O'Neill]

I stopped using acid stop baths when I used ADOX CHS Art Films,

When I used Kodak IR sheets films, I used a very mild acid stop bath containing 1 tsp of citric acid. A regular acetic acid stop bath almost always resulted in pinholes in the emulsion. I also found that Efke 25 preferred citric acid.

Rod, how did you like Adox CHS?

[Regular Rod]

Question, do you know how long the water needs to be there before the film fully stops developing?

Is it 10 seconds or 30 seconds or 2 minutes? With water I mean...

Ilford recommends 1 minute for ilfostop but I always rinse once or twice with water after the dev anyway so as to make the stop last longer without dev contamination. So, by the time the ilfostop gets to the film, have I already stopped it?
Pour in. Four agitations left right, four agitation back front. Pour out. Pour in more. Four of each as before. Pour out. Pour in Fixer. Start clock. Four of each repeated until first minute is up. Stand one minute. Four of each. Stand until that minute is up. Four of each again. Stand again. Keep doing it until the five minutes is up. Pour out fixer into jug. Wash according to Ilford method. For sheet film in the Paterson Orbital it is still the Ilford method but with the four of each agitation just continued for 10 seconds, then 20 seconds, then one minute, then another minute and two more minutes after that. Then a stand in water with 0.5ml of Mirasol in 500ml of water for one minute. Very slight agitation, more a roll round with the lid off so I can see that I make no bubbles, about every 15 seconds. Then carry tray and film through to drying cabinet. Clip up the film by a corner, still in the water. Lift it out smoothly and hang it up to drip dry. After five minutes blot the great big drop off each lower corner with a tightly folded tissue so that only the very edge of the corner actually gets touched. Then dry it.

RR

[Regular Rod]

When I used Kodak IR sheets films, I used a very mild acid stop bath containing 1 tsp of citric acid. A regular acetic acid stop bath almost always resulted in pinholes in the emulsion. I also found that Efke 25 preferred citric acid.

Rod, how did you like Adox CHS?

I only used CHS in 120. I loved the CHS 25 ART for its tonal range, reasonably fine grain and the way it responds to both 510-PYRO and OBSIDIAN AQUA. I did however hate the substrate! It was very lively and loading it into the spiral was always nerve wracking. After processing it remains a nightmare, spiralling into cylinders when I cut it up to 6x12 negatives. Getting it into a negative holder was always a struggle, darkroom gloves were a great help as they let me grab the film anywhere instead of by the edge only. The best negative holder for this film uses ANR glass to lay it down flat. I would gladly put up with all these torments for the results it gave. I currently am down to my last 7 frames of CHS 25 ART...

Anyway I liked it so much I am about to try CMS 20 with OA. If I can have some nice tones I will be happy again...
:D
RR

[Lachlan 717]

Ilford recommends 1 minute for ilfostop but I always rinse once or twice with water after the dev anyway so as to make the stop last longer without dev contamination.

I use a SB with indicator; however, I have never had the indicator react. I do change my SB about every month. The SB I use is 1:19, so a one litre bottle (under $20) lasts over 18 months at a cost of approx. $1/month.

As such, I don't understand why you'd risk your images to save so little $$$.

[Andrew O'Neill]

and less odour compared to their rapid fixer.

should have read, ...compared to regular acid stop bath.

[StoneNYC]

Pour in. Four agitations left right, four agitation back front. Pour out. Pour in more. Four of each as before. Pour out. Pour in Fixer. Start clock. Four of each repeated until first minute is up. Stand one minute. Four of each. Stand until that minute is up. Four of each again. Stand again. Keep doing it until the five minutes is up. Pour out fixer into jug. Wash according to Ilford method. For sheet film in the Paterson Orbital it is still the Ilford method but with the four of each agitation just continued for 10 seconds, then 20 seconds, then one minute, then another minute and two more minutes after that. Then a stand in water with 0.5ml of Mirasol in 500ml of water for one minute. Very slight agitation, more a roll round with the lid off so I can see that I make no bubbles, about every 15 seconds. Then carry tray and film through to drying cabinet. Clip up the film by a corner, still in the water. Lift it out smoothly and hang it up to drip dry. After five minutes blot the great big drop off each lower corner with a tightly folded tissue so that only the very edge of the corner actually gets touched. Then dry it.

RR

Haha no need to give me your whole dev process hahaha :)

But thanks.

[Regular Rod]

Haha no need to give me your whole dev process hahaha :)

But thanks.

Oops! I get carried away sometimes. Sorry about that.
:o
RR

[StoneNYC]

Oops! I get carried away sometimes. Sorry about that.
:o
RR

No worries, I do too.

[lbenac]

Hi Luc, I get my chemicals from Nymoc in Toronto. Email John Burrows: nymoc@bellnet.ca

Thanks Andrew, I have a fresh supply of HD and MC but will contact them next. SHipping the pyrocat from the USA has become a little bit expansive.

[Andrew O'Neill]

First time I ever photographed in a Canadian rain forest. I don't normally shoot trees. Just down the road from my house. Semi-stand in Obsidian Aqua. 45 minutes, three agitation cycles, one minute at the start, a third of the way in, and two thirds in, 10 seconds each. BTZS tube, filled to the brim (1200ml total solution). 21C.
It's quite sharp compared to my previous example. Same lens was used. I'll have to play around with dilution. I think a more dilute solution will end up looking more like the results that I can get with a very dilute pyrocat-hd. Looks like it could make a good compensating developer, too.
Down to the darkroom to make some glop!

[StoneNYC]

First time I ever photographed in a Canadian rain forest. I don't normally shoot trees. Just down the road from my house. Semi-stand in Obsidian Aqua. 45 minutes, three agitation cycles, one minute at the start, a third of the way in, and two thirds in, 10 seconds each. BTZS tube, filled to the brim (1200ml total solution). 21C.
It's quite sharp compared to my previous example. Same lens was used. I'll have to play around with dilution. I think a more dilute solution will end up looking more like the results that I can get with a very dilute pyrocat-hd. Looks like it could make a good compensating developer, too.
Down to the darkroom to make some glop!

Hmm what film is that? It has this weird glow to the edges, cool :)

[Andrew O'Neill]

FP4. But I believe the glow is due to back lighting.

[StoneNYC]

FP4. But I believe the glow is due to back lighting.

I'm sure it's just unique, must be perfectly centered between to hit both sides? Anyway it's great

[Andrew O'Neill]

It's fairly centred, but I lost some of the sun when I went to make the exposure.

[gth]

Wonder what happened to Jay….. seemed he had mellowed a bit and was enjoying taking portraits of his wife with his RB.

Last he was heard of he got caught up in a stupid thread about banning of FP, moderation and the like that means "nothing to nobody"…. anyhow, hope he is still dabbling with developers.





I'd like to introduce a new developer I've been testing for some time, and will continue to test and use. I call it Obsidian Aqua, for its scalpel-sharpness and water base.

Obsidian Aqua is very closely related to Hypercat II, but takes advantage of some of the opportunities an aqueous solution provides for economy, without sacrificing keeping prperties. The main reason for using propylene glycol in Hypercat II is to extend its keeping properties, but this comes at at some cost. PG is not locally available in many places, and is expensive to ship, and adds considerable expense to the developer. In Obsidian Aqua I've tried to maximize keeping properties while minimizing expense, including shipping costs, by utilizing locally available ingredients where possible, including the use of distilled water as the solvent. Like Hypercat II, OA uses catechol as its sole developing agent, but OA is preserved by metabisulfite in the stock solution, instead of ascorbic acid, and retains carbonate as the accelerator. OA can be made up in sodium or potassium metabisulfites and carbonates, depending on availability.

To maximize the keeping properties, the stock solution is highly concentrated. This allows for a higher ratio of catechol to metabisulfite, and a lower ratio of metabisulfite to water compared to other catechol staining developers, which simultaneously improves stain formation and keeping properties. A working solution of catechol/carbonate developer with appropriate carbonate content requires practically no preservative. The preservative is primarily required for the stock solution.

To make a working solution, the OA stock solution is dissolved into a solution of 6.66% carbonate, and how this is managed will depend on the carbonate used, and the preferences of the photographer. A 66.6% solution of potassium carbonate can be made by dissolving 666g of potassium carbonate to make 1 liter of stock solution, or 6.66g of either carbonate can be dissolved in a liter of water to make a working solution, or any number of other possibilities. The important thing is that the working developer contains 6.66g of carbonate/ liter.

Obsidian Aqua

Distilled water 700ml
Metabisulfite (sodium or potassium) 20g
Catechol 250g
Distilled water to 1 liter

Dilute 1:500 with 6.66% carbonate solution (sodium or potassium, depending on which metabisulfite is used in the OA stock solution). 1 liter of Obsidian Aqua makes 500 liters of working solution.

Develop TMY-2 12:00 @ 70F with *geometric agitation sequence.

Obsidian Aqua produces negatives of unsurpassed sharpness, excellent gradation, very fine grain, and full film speed. OA can be used with rotary processing, but with some loss of film speed. I hope this developer will be more convenient for my friends overseas, who often need to order supplies from outside their own countries. I highly recommend Artcraft Chemicals (http://www.artcraftchemicals.com/products/products-page/general-chemistry/a-m/catechol-part-1660/) for catechol. Artcraft offers 250g of catechol, which wouldn't require any weighing of the chemical to make up the stock solution; just mix the entire amount to make 1 liter. The metabisulfite is not critical, and could be measured with measuring spoons if no scale is available. 1 level teaspoon of metabisulfite weighs approximately 6.5g, so 3 tsp/ liter is close enough.

Obsidian Aqua stock solution should keep very well. Though I have no stock solution older than 6 months, I expect it to last at least a year in a partially full glass bottle. Time will tell.:)

I hope this formula is useful for anyone desiring the sharpest possible negatives with the best overall Image Quality, at the least possible expense, wherever one might live.


* The notion of a geometric agitation sequence was recently suggested to me, and I've been using it with good results. My method is as follows:

I use a count up timer, and begin by agitation continuously for 1 minute. Then I reset the timer and agitate for 10 seconds, according to the following progression (in minutes): 2, 4, 8, 16, 32, etc.

A geometric agitation sequence seems appropriate for this kind of very dilute developer, and my results bear this out.

[mikoyan]

http://www.flickr.com/groups/pyrodeveloper/discuss/72157629337969407/
http://www.flickr.com/groups/pyrodeveloper/discuss/72157632252062346/
http://www.flickr.com/photos/jay_defehr/

[gth]

Thanks for that…good to see!

[Regular Rod]

Wonder what happened to Jay….. seemed he had mellowed a bit and was enjoying taking portraits of his wife with his RB.

Last he was heard of he got caught up in a stupid thread about banning of FP, moderation and the like that means "nothing to nobody"…. anyhow, hope he is still dabbling with developers.

Please tell us what RB and FP are?

RR

[Taija71A]

Please tell us what RB and FP are?

____

Rod... 'RB' refers to the Mamiya RB67 Camera that Jay sometimes uses with his Mamiya 150mm f/4.0 SF-C Soft Focus lens and 'FP' refers to a previous LF Forum Member... Who now hangs out on 500px (I believe).
--
Best Regards,

-Tim.
________

[Regular Rod]

____

Rod... 'RB' refers to the Mamiya RB67 Camera that Jay sometimes uses with his Mamiya 150mm f/4.0 SF-C Soft Focus lens and 'FP' refers to a previous LF Forum Member... Who now hangs out on 500px (I believe).
--
Best Regards,

-Tim.
________

Oh. Thank you.

RR

[Andrew O'Neill]

I posted this one in the xray comparison thread, but thought I'd post it here as it was developed in Obsidian Aqua. The negative is very sharp. I used Kodak single-sided xray. The scan however, doesn't do the sharpness justice...

[Jan Pedersen]

As I am still trying to find the reason for my failed attempt to make this developer work I am curious as to what those who use it mix it up with.
Is it Sodium Metabisulfite and Sodium Carbonate or is it Potassium Metabisulfite and Potassium Carbonate?
I have only tried the Sodium variant and that is clearly not right.
Will try with the Potassium variation when I get the Potassium Metabisulfite next week.

How does a negative look? Somewhat similar to a Pyrocat negative?
Thanks.

[Andrew O'Neill]

If you go back to page 10 of this thread, you can see some comparison shots between OA and Pyrocat-HD. They are both very similar, with OA having slightly, very slightly more sharpness. That difference could only be seen with an extreme enlargement. What I appreciated about OA was it only requires 3 chemicals, that mix up quickly.

[Jan Pedersen]

Thanks Andrew. I did see the positive (Print) comparison but I am more curious about the negatives.
So far I have almost no image on my negatives, they are so clear that not even a scanner can pick up enough information to make an image.
As I posted above I have not yet tried the Potassium variation but have used fresh Catechol but a bit old Sodium Metabisulfite in the A solution.
Being as stuborn as I am I find it difficult to give up getting this to work. :(

[Regular Rod]

Thanks Andrew. I did see the positive (Print) comparison but I am more curious about the negatives.
So far I have almost no image on my negatives, they are so clear that not even a scanner can pick up enough information to make an image.
As I posted above I have not yet tried the Potassium variation but have used fresh Catechol but a bit old Sodium Metabisulfite in the A solution.
Being as stuborn as I am I find it difficult to give up getting this to work. :(

Hello Jan

With such thin negatives, the only thing I can think of is that somehow the exposure was insufficient. Have you checked your meter, lens and shutter for a possible malfunction? Can you try again with different meter, lens and shutter?

RR

[richardman]

With the high concentration, I think this is also great for travel-and-develop scenario, especially in flying situation, 100ml each can go a long way... Has anyone try it?

[Jan Pedersen]

Thin negatives always point to lack of exposure I agree but in this case the film base is clear even in the rebate. I have used different cameras and have developed film in other developers with perfect result so this is a developer problem for sure.

[Andrew O'Neill]

Jan, which film are you using? I had to increase to 10ml of OA when developing TMY2. Got much better densities then.

[Jan Pedersen]

Have tried with TMY, HP5+, FP4+ and Pan-F same extremely thin negatives.
10ml of OA to what total volume?

Not sure it makes any difference but are you using the Sodium or the Potassium variant?

[StoneNYC]

Have tried with TMY, HP5+, FP4+ and Pan-F same extremely thin negatives.
10ml of OA to what total volume?

Not sure it makes any difference but are you using the Sodium or the Potassium variant?

If there are so many variants, and some of them don't work how come they exist, how come they haven't been dispelled as no good, I don't really understand this developer, nor why it would work better than any other, but if so many people are having problems with it then obviously it doesn't work in every situation, whether it's because somebody's tapwater is different than someone else's, maybe somebody has a well and so all the minerals are affecting the outcome etc. but either way I don't understand how this can be an effective developer with so many issues.

[Regular Rod]

If there are so many variants, and some of them don't work how come they exist, how come they haven't been dispelled as no good, I don't really understand this developer, nor why it would work better than any other, but if so many people are having problems with it then obviously it doesn't work in every situation, whether it's because somebody's tapwater is different than someone else's, maybe somebody has a well and so all the minerals are affecting the outcome etc. but either way I don't understand how this can be an effective developer with so many issues.OA has no issues whatsoever! Jan has a problem and without being there with him, I'm not sure how we can help him fix his problem.

In the interests of clarity and consistency here is the recipe that I use without any problems:
104759

The only thing left that I can think of that might account for the thin negatives, was the sodium carbonate anhydrous ?

RR

[Jan Pedersen]

The only thing left that I can think of that might account for the thin negatives, was the sodium carbonate anhydrous ?

RR

Yes. Now tell me that is not going to work :)

[Jan Pedersen]

To Stone NYC,

There are only two variations to this simple developer apart from concentrations as with any other developer why I am even more perplexed that I get so poor results.

[Andrew O'Neill]

StoneNYC, it worked for me. I use the same formulation as RR, but I use 5ml of OA for the working solution for FP4 and X-ray. 10ml for TMY-2. My tap water sucks, but it works fine.

[Taija71A]

____

Jan, I just sent you a PM with some info -- Okay?
--
Your use of Sodium Carbonate (Anhydrous) as compared to Sodium Carbonate (Monohydrate) would not (*In itself) cause the problems... That you are currently experiencing. :(
--
Regards,

-Tim.
________

[Jan Pedersen]

Andrew, it does not mean much to use 5ml or 10ml unless we know what your total volume of developer is ;)
10ml of OA in 500ml of water is quite concentrated, I guess I could try :)

I do by the way always use distilled water for my developers.

[Regular Rod]

Yes. Now tell me that is not going to work :)

No Jan, that is correct to use anhydrous. It's a real puzzle. I wish you were nearby. I'd send you some of my A and B...
:confused:
RR

[onnect17]

Just developed a piece of Double-X exposed at 1600 using 1:1:100 for 8 min and 72 degrees in the Jobo. I used Pyrocat's-HD part B as the part B.
10ml of developer per square inch of film. The negative looks fine.

[onnect17]

Tested another strip of the same negative with Pyrocat-HD and I'm can't say OA is sharper. I noticed however more grain and less detail in the shadows in the OA negative. I already PMed Andrew to take a look again at his negs.
I usually do the testing using strips of the same negative to avoid any chance of shaking, different exposure or any other issue.

[Jan Pedersen]

And we have a STAIN
Can't believe it but a fresh A solution with Potassium Metabisulfite received today made a big difference.
Same dilution as I previously used, 1ml A, 5ml B in 500ml water. This time 120 Acros film and it looks good as I hangs to dry.

Now it is time to fine tune.
Thanks for all the suggestions and help.

[Taija71A]

And we have a STAIN... Can't believe it but a fresh A solution with Potassium Metabisulfite received today made a big difference...
Now it is time to fine tune. Thanks for all the suggestions and help.

____

Good Stuff Jan!!!
Glad to see that you stuck with it... And that you are now making Real Progress! :D
--

-Tim.
________

[Regular Rod]

And we have a STAIN
Can't believe it but a fresh A solution with Potassium Metabisulfite received today made a big difference.
Same dilution as I previously used, 1ml A, 5ml B in 500ml water. This time 120 Acros film and it looks good as I hangs to dry.

Now it is time to fine tune.
Thanks for all the suggestions and help.

Deo Gratias!

:-)

RR

[Andrew O'Neill]

I went back and checked the negatives again, and the OA still has a very slight edge in sharpness overall, in the shadows highlights, etc., to my eyes. I only did this test once, mind you.

[Jan Pedersen]

Deo Gratias!

Mange Tak!


I went back and checked the negatives again, and the OA still has a very slight edge in sharpness overall, in the shadows highlights, etc., to my eyes. I only did this test once, mind you.

Extra sharpness is fine but if I can get even developed negatives and no edge effect on 120 roll film I will be satisfied.
I don't intend to use OA for LF negatives as I always process those in a Jobo.

[lbenac]

I don't intend to use OA for LF negatives as I always process those in a Jobo.

Because of the loss of film speed?
>>>
OA can be used with rotary processing, but with some loss of film speed
and rotary processing costs up to a full stop, or about 1/2-2/3 stop under box speed
<<<

Cheers,

Luc

[Jan Pedersen]

Luc, One of the reasons but I might try it if I can get the tonality I like from smaller formats. Another reason is uneven development, I don't know if OA will give me that problem but Pyrocat MC certainly did.
For LF I have pretty much settled on FX37 as it give me a good speed increase with TMY.

[onnect17]

Hi Andrew,
Thanks for checking. A couple of questions:
How about grain size in the dark areas?
Did you used the same development method? Time? Temperature? Agitation? I used the jobo at 72 degrees and development between 8 and 10 minutes for both developers. Double-X emulsion, EI 1600.





I went back and checked the negatives again, and the OA still has a very slight edge in sharpness overall, in the shadows highlights, etc., to my eyes. I only did this test once, mind you.

[Andrew O'Neill]

Hi onnect17, the grain appeared similar through all tones in the negative. At least I couldn't see any difference. Both negatives received exactly the same development method, temperature, and agitation. The OA negative was ever so slightly less dense in the highlights, as I did not complete any N tests.

How do you like Double-X overall? How does it behave at 1600? I've signed up for the 4x5 special order. Hope it goes through.

[onnect17]

Hi Andrew,
Thanks for checking again. I'm using aerial double-x. I developed it in OA 1:1:100 for 8 min and in Pyrocat-HD 2:2:100 for 10.
I wish the forum had a temp folder to drop some samples but you can PM me with your email if you are interested in the original file. Here's a partial 4x10. It's 15MB well compressed jpeg.
The strip in the top was develop in Pyrocat-HD. The middle in two baths OA 1:20. The bottom with regular OA.
105122

[Taija71A]

If I try this what difference will I actually see in an 8x10 contact print compared to developing in Pyrocat HD? Will there be an observable 'improvement' in the image?


If you go back to page 10 of this thread, you can see some comparison shots between OA and Pyrocat-HD. They are both very similar, with OA having slightly, very slightly more sharpness.
That difference could only be seen with an extreme enlargement.

____

Simple Answer:

'Virtually' NONE! :)
--
Best Regards,

-Tim.
_________

[Regular Rod]

The differences are:

OA: Solute = Water
P-HD: Solute = Propylene Glycol (at 155 deg F)

OA reagents: = Sodium Metabisulphite, Catechol and Sodium Carbonate
P-HD reagents: = Sodium Metabisulphite, Pyrocatechin, Phenidone, Potassium Bromide and Potassium Carbonate

OA dilution: = 1:500 to 1:1,000
P-HD dilution: = 1:100

OA costs less to make and costs less to use.

For the differences in the photographs, surely we should decide for ourselves based on our own preferences. In my case I like OA - a lot!
:)
RR

[Jan Pedersen]

The fact that OA is less expensive to use than most other developers I think will have very little influence in the decision making process.
When we get to the point where we use large pieces of negatives to get the best possible image quality that we can get, cost of developer will be way down the list of what's important.

It is obviously to early for me to say whether OA looks any different or better than what Pyrocat variations can do but what I have seen from a printing session yesterday I still fail to see it's attraction.
Printing with alternative processes may change that view but for silver gelatin printing I don't see the OA to be anything special over commercially available developers.

[onnect17]

I understand mixing 2 ingredients is of course easier than 4 but I do not think OA is cheaper.
The 1:500 mix in OA is for semi-stand development. Try 1:500 in the Jobo and the negative will look more like a piece of Pictorico.
The semi-stand and stand with PCHD also calls for 1:500 dilutions.
The cost of part B is similar but part A is cheaper with PCHD. One liter of PCHD part A costs around $6 in water and $11 in glycol. One liter of part OA part A costs around $26. Cost calculations based on ArtCrafts Chemicals and Essential Depot prices.

In any case, as the previous post mentioned, is not about the cost of the developer, which is nothing compared to the rest (film, etc.).


The differences are:

OA: Solute = Water
P-HD: Solute = Propylene Glycol (at 155 deg F)

OA reagents: = Sodium Metabisulphite, Catechol and Sodium Carbonate
P-HD reagents: = Sodium Metabisulphite, Pyrocatechin, Phenidone, Potassium Bromide and Potassium Carbonate

OA dilution: = 1:500 to 1:1,000
P-HD dilution: = 1:100

OA costs less to make and costs less to use.

For the differences in the photographs, surely we should decide for ourselves based on our own preferences. In my case I like OA - a lot!
:)
RR

[Regular Rod]

You might want to shop around a little if that is what it costs you for the OA reagents. I had to import mine from Poland but it still came to nothing like $26 to make up a litre of stock solution A...

RR

[onnect17]

I buy most of the chemicals at Artcraft Chemicals. How much did you pay for 250g of catechol from Poland?

[Regular Rod]

I paid €70.00 for 1 kilo in 2012 so I was wrong to imagine there was a BIG saving as that works out at $23.71 per 250g. My apologies.
:o
RR

[onnect17]

No apologies needed. It's always good to discuss about sources and cost for chemicals.

[Michael Kadillak]

Have never mixed Pyrocat HD with anything but water. Very simple and inexpensive as well.

If the difference is not anything that I can actually see in the final prints - why change?

Add in that Sandy King is a good guy and I'll stick with it.

Times two on all counts. Sandy is and has always been a distinguished dignitary academically and within the photographic community. They don't come any better.

[Andrew O'Neill]

Ken, I dry-mount scanned the negatives with a V750. Full negatives at 600dpi. 48bit colour. For the smaller samples I scanned in at 4800dpi. I kept the green channel and eliminated red and blue channels in PS. No sharpening.

Personally, I like pyrocat-hd and OA and will use them both.

[C_Remington]

If it's as good as the name you picked for it, I'll have to try it! Maybe you should be
in marketing!

Indeed. Marketing.

[Regular Rod]

Indeed. Marketing.

I don't understand this attempt at cynicism. No one is being forced to even read about OBSIDIAN AQUA let alone make it and use it. An attractive aspect of OBSIDIAN AQUA is that it is being used purely on its merits. There is no marketing, nothing is for sale. The formula has been given by its inventor, free, gratis and for nowt, to us all. It is published in the public domain for all to see, consider and, if so minded, to make and use. It is a very useful developer.

RR

[Taija71A]

Indeed. Marketing.


I don't understand this attempt at cynicism. No one is being forced to even read about OBSIDIAN AQUA let alone make it and use it. An attractive aspect of OBSIDIAN AQUA is that it is being used purely on its merits. There is no marketing, nothing is for sale. The formula has been given by its inventor, free, gratis and for nowt, to us all. It is published in the public domain for all to see, consider and, if so minded, to make and use. It is a very useful developer. RR

____

Rod, agreed in full 110% :D
--
I think that some people are unable to accept, that Obsidian Aqua and/or the latest version of Hypercat are just as good... If not Perhaps? even slightly better (*On some individual counts) -- Than Pyrocat-HD.
--
Best Regards,

-Tim.
________

[catalinajack]

For those of you who prefer to use rotary processing (Jobo) and are okay with a slight reduction to box speed, what length of time at what temperature do you for specific films? I use only Delta 100 and T-max 400 (4 x 5). And aside from the loss of box speed, are the results any different than processing semi-stand?

[onnect17]

The oxidation of the developer is directly linked to the agitation which depends of the speed and design of the tanks in the Jobos. Also, the amount and/or concentration of developer solution needs to be considered, so allow me to suggest using 2:2:100 instead of the regular 1:1:100 and start your tests on the 5 min mark.

[catalinajack]

[QUOTE=Regular Rod;1059754]I don't think dry Catechol goes off if sealed in a jar. In fact I believe that is one of the characteristics that Jay took into consideration when he was devising OA to last indefinitely.

Did you use Sodium Metabisulphite in your solution A? I think we are supposed to use Sodium Carbonate in Solution B if we use Sodium Metabisulphite and if we use Potassium Metabisulphite in solution A we should use Potassium Carbonate in solution B

Here's how I make up mine after Jay explained to me how I could save on the quantities of distilled water needed:

OBSIDIAN AQUA

Solution A
Distilled Water - 300 ml
Sodium Metabisulphite - 8 g
Catechol - 100 g
Distilled Water to make - 400 ml

Solution B (Concentrate)
Distilled Water - 4 litres
Sodium Carbonate Anhydrous - 1 kilo
Distilled Water to make - 5 litres

Working Solution
Solution A - 1 ml
Solution B - 12.5 ml
Tap Water to make - 500 ml

Try 12 minutes @ 20 degrees C semi-stand to start with. That is 60 seconds gentle agitation followed by 10 seconds gentle agitation every two minutes. A pre-soak in water at 20 degrees C seems to ensure even development quite nicely.


I tried 12 minutes at 20C, agitating every two minutes. Tried twice and got only totally clear negatives, NOTHING! I checked and double-checked the formulae and the mix I used to develop. No mistakes. I used 2.6ml of Solution A, 32.5ml of Solution B added to 1300ml of water. What am I doing wrong. I got the chemicals fresh from Artcraft. Am using sodium rather than potassium.

[Jan Pedersen]

Sounds like you have exactly the same problem as I did.
In the end I made the OA with Potassium Metabisulphite and Potassium Carbonate and can make good looking negatives now. TMY an exception, those negatives are still much to thin but Fuji Acros and Plus-X (Small format) looks good.

Did you get all chemicals fresh or just some of them?

[catalinajack]

Got them all fresh from Artcraft. I will try the potassium varieties but I wonder why you are still getting thin negatives with TMY. For me, I am certain it's the developer cuz I took a baseline shot and developed it using Xtol. My film? Delta 100. And, of course, all of my other shots have been taken under constant lighting and the same stop and shutter speed. It's not exposure variances for certain. It seems the developer using the sodiums are wiping everything from the film. Perhaps the times should be much shorter.

[Jan Pedersen]

At this time we must conclude that it is consistently inconsistent and to much of a risk to use on important images.

[Regular Rod]

It is a puzzle. I have experienced nothing but good results from OBSIDIAN AQUA since I started using it. Today I developed three films all at the same 1:500 mix, all at 20 deg. C and all at 12 minutes semi-stand. The films were HP5 Plus 120, HP5 Plus 35mm and ADOX CHS 25 Art 120. My best pal uses ILFORD's Delta films including Delta 100 and gets great results from OBSIDIAN AQUA too (http://www.flickr.com/search/?w=21163290@N05&q=Delta).



I just cannot imagine what is causing this problem for you...

RR

[onnect17]

The oxidation of the developer is directly linked to the agitation which depends of the speed and design of the tanks in the Jobos. Also, the amount and/or concentration of developer solution needs to be considered, so allow me to suggest using 2:2:100 instead of the regular 1:1:100 and start your tests on the 5 min mark.

I'm talking about Pyrocat-HD, forgot to mention.

[onnect17]

At this time we must conclude that it is consistently inconsistent and to much of a risk to use on important images.

I wonder if the issue is the sodium carbonate vs potasium carbonate. Part B of Pyrocat-HD can be used for the tests.

Anybody with good results using sodium carbonate?

[Regular Rod]

Mine is all made with Sodium Metabisulphite and the Sodium Carbonate (anhydrous).

RR

[mikoyan]

me too.

[onnect17]

Good, so it's not the sodium carbonate. How about agitation, who's using 1:1:500 with the jobo?

[Regular Rod]

Good, so it's not the sodium carbonate. How about agitation, who's using 1:1:500 with the jobo?

Now then! Have I spotted a problem here?

1:1:500? If we are talking 1 of Solution A and 1 of Solution B and 500 of water that would probably be wrong.

1 of solution A plus 12.5 of solution B made up to a total of 500 with water would be correct.

104759

RR

[onnect17]

Sorry, I meant 1:500.
BTW, I read some posts from Jay here (https://www.flickr.com/groups/pyrodeveloper/discuss/72157629337969407/) where he mentions some issues with OA and TMX and also with processors.

I like 510-Pyro better, IMHO. During tests with small tanks, some edges did look sharper than PC-HD but I stopped using it after finding what it seems small pinholes in the 35mm negatives. It also works just fine with the Jobo, which it's a "must" in my case.



Now then! Have I spotted a problem here?

1:1:500? If we are talking 1 of Solution A and 1 of Solution B and 500 of water that would probably be wrong.

1 of solution A plus 12.5 of solution B made up to a total of 500 with water would be correct.

104759

RR

[catalinajack]

Approaching success, I think. I mixed another batch using the potassiums rather than the sodiums. Yes, I know others have had success with the sodiums. Using Delta 100, I was able to produce a negative, albeit very thin. I developed at 68F for twelve minutes agitating every two minutes and got a thin negative. Next I developed at 70F for fourteen minutes and produced a better negative, but still thin. Then I did the unconventional. I doubled the amount of Solution A and developed at 70F for 12 minutes. It produced a negative wherein I could finally see the definition of the mortar between my floor tiles in the basement but I am concerned because, to do so, I had to go way outside the formula. Plus, I think the negative is still a little thin. I'm tired so tomorrow I will extend the development time to 14 minutes and see what I get.

Question: with the staining, should a properly developed and exposed negative look roughly the same as concerns density, but brownish, as with standard developers, Xtol for example?

[Jan Pedersen]

I think part of the reasons for thin negatives is the film speed. Those few rolls I have successfully developed in the Potassium variant have been exposed at about half box speed.
Negatives developed with Catechol looks thinner than negatives developed in Xtol so please don't let that deceive you. In my experience with Pyrocat a thinner looking negative still took longer to expose than a negative developed in a solvent developer.

[Jan Pedersen]

That is one thing I still need to try. Going by the suggested dev times I have developed a few rolls that looks nice without extended time. Just very inconsistent so far.
Next time I will cut a roll in half and give half the roll two more minutes to see what the difference is.

[Andrew O'Neill]

Here is a comparison of a sheet of 8x10 xray film developed in OA with intermittent agitation and a sheet given stand development in a BTZS tube.
The stand negative is pretty ugly, tonally, and the bromide drag is a drag... but edge effects are stunning. I much prefer the tones of the intermittently agitated film.

[Peter Collins]

How much (in ml) working solution are folks using per each 4x5 sheet of film? Please chime in! And thanks!

[Regular Rod]

How much (in ml) working solution are folks using per each 4x5 sheet of film? Please chime in! And thanks!
I like to use 500ml of working solution for 4 sheets of 4x5.

RR

[onnect17]

Here is a comparison of a sheet of 8x10 xray film developed in OA with intermittent agitation and a sheet given stand development in a BTZS tube.
The stand negative is pretty ugly, tonally, and the bromide drag is a drag... but edge effects are stunning. I much prefer the tones of the intermittently agitated film.

Thanks for posting the results of your tests!

I wonder how they compare to 5 secs /min.

[Tony Lakin]

Hi
Anyone know what should be the temperature of the 750ml of distilled water to which Catechol and Meta are added.

Thanks

[Regular Rod]

They dissolve in the distilled water at room temperature (say 20 deg. C) reasonably easily with stirring. You could speed the process by warming it up a little bit. Sodium Metabisulphite in first, dissolve all, then Catechol, dissolve all is the correct order.

RR

[Tony Lakin]

Many thanks, much appreciated:)

[Tony Lakin]

Hi
I wish to try Obsidian Aqua 1ml to 1 litre for Tech Pan, do I need to halve the sodium carbonate, ie 2.5 grams to 1 litre instead of the 5 grams required at 1 to 500 dilution?

[Regular Rod]

Hi
I wish to try Obsidian Aqua 1ml to 1 litre for Tech Pan, do I need to halve the sodium carbonate, ie 2.5 grams to 1 litre instead of the 5 grams required at 1 to 500 dilution?

Yes. Put in half the amount of solution B as well. So...

Solution A 1ml into say 500ml of water then add 6.25ml of solution B then add water to make up to 1litre.

RR

[steveo]

Can I ask a newbie question. If I bought a 2kg bag of Anhydrous Sodium Carbonate how much solution B would this make and how much of it would I add to the working solution? Also the working solution looks something like 1ml of A to ??ml of b topped off with water to make 500ml?

Edit: Found an earlier post by Regular Rod which suggests 1kg of the Carbonate to make 5l then using it 1:12.5 topped up to 500ml have I read this correctly?

[Taija71A]

__

Please read:

http://hypercatacutancedeveloper.blogspot.ca/2012/07/obsidian-aqua.html

The answers to your questions are clearly explained above. Thank-you!
--
Personally, I would start by making something like a 20% Sodium Carbonate (200g/liter) Stock Solution.
--
Regards,

-Tim.
_________

[steveo]

Cheers Tim, that was the first one I stumbled across but I'm still a little confused by the second solution. Do you make up a large supply of very weak B instead of a stronger B?

[Taija71A]

... Do you make up a large supply of very weak B instead of a stronger B?

The Sodium Carbonate Stock (200g/liter) Solution (*That I suggest you make) ... Is your 'Stronger' B.

You of course, are 'free to make up' your Sodium Carbonate Stock Solution at a 'weaker' Dilution... But it won't keep as well.
--
Cheers!
_________

[steveo]

Right, missed that sorry.
So you have 1ml A + 100ml B + 400ml water?

[Taija71A]

... So you have 1ml A + 100ml B + 400ml water?
__

No.
--
As a 'Starting Point'... Your 'Working' Developer needs to contain approx. 5g of Sodium Carbonate per/L.

You just added 20g of Sodium Carbonate to your 500ml of Working Developer.
(*100ml/1000ml x 200g/liter) = 20g.
--
Please get back with the correct amount of 'B' Stock Solution to add -- Okay?
--
Thank-you!

-Tim.
_________

[steveo]

Okay I think I've got my head round it.

Working should be 5g/l, (this) stock is 200 g/l, so 1l would have 25ml of the working solution; 500ml would need 12.5ml

[Taija71A]

Okay I think I've got my head round it.

Working should be 5g/l, (this) stock is 200 g/l, so 1l would have 25ml of the working solution; 500ml would need 12.5ml
__

Excellent! :)

12.5ml is... The 'Correct' answer.
(*I of course could of told you the answer...
But you now have the 'Satisfaction' of being able to figure it out -- Yourself!).
--
Best regards,

-Tim.
_________

[steveo]

:D

And of course if I mess with the B stock solution I can work out my own variables.

[Taija71A]

:D And of course if I mess with the B stock solution I can work out my own variables.

Exactly! :D

[steveo]

Is there a practical limit to how much Sodium Carbonate can be dissolved in water?

[Taija71A]

Is there a practical limit to how much Sodium Carbonate can be dissolved in water?
__

Yes... Approx. 200g/L.
_______

[steveo]

__

Yes... Approx. 200g/L.
_______

Fair enough :)

[Regular Rod]

Can I ask a newbie question. If I bought a 2kg bag of Anhydrous Sodium Carbonate how much solution B would this make and how much of it would I add to the working solution? Also the working solution looks something like 1ml of A to ??ml of b topped off with water to make 500ml?

Edit: Found an earlier post by Regular Rod which suggests 1kg of the Carbonate to make 5l then using it 1:12.5 topped up to 500ml have I read this correctly?

Yes.

RR

[steveo]

Got all my chemicals mixed the other day and done a test roll of GP3 at the weekend and it worked! Thanks for the help guys.

Need to get an inversion lid for my Jobo before I can start doing 54 with this stuff.

[Jon Wilson]

Resurrecting this thread and hope to bring it new life.
Does anyone have any additional developing suggestions for various films in a jobo? I just mixed up a liter of AO today and want to see what I can do.
Thanks. JW

[mikoyan]

Hello
In a jobo the problem will be oxidation... You will probably have to use higher concentration, slow rotation rate, shorter dev time and more sulfite... Or the base + fog may be too high.
To my mind, there are better alternatives for jobo. But just try !

[Jon Wilson]

Hello
In a jobo the problem will be oxidation... You will probably have to use higher concentration, slow rotation rate, shorter dev time and more sulfite... Or the base + fog may be too high.
To my mind, there are better alternatives for jobo. But just try !
Good point. In an effort to process more film while working on my learning curve, I have brought AO home with 35mm & 120mm tanks. Plan to develop some bulk ISO 400 film. Will start between 5-7 min and see what I get.

[bentbikr]

Ferric ammonium EDTA

[GoodOldNorm]

Just mixed up a batch of OA, for solution B the formula specifies 200g sodium carbonate (anhy) I have washing soda crystals. According to the darkroom cookbook in the conversions section if the formula specifies sod. carbonate (anhy) And you have sod. carbonate crystal you should multiply the specified amount by 2.7. This gave me 200g sod carbonate (anhy) x 2.7 = 540g of sod carbonate (crystal). So I gradually mixed 540g of the crysttal in room temperature water, it has taken an eternity to get the sod. carbonate into solution. I have been stirring for ages, I then transferred the solution into 2 one liter bottles and did a gentle "Indian Club" workout. My shoulders have loosened up great but my B solution still looks cloudy :-( Is the 462g ever going to fully go into a clear solution or have I got the amount wrong? What should the ph of bath B be? With a simple litmus paper test mine is reading ph11 or more (my papers only read to ph11).

[GoodOldNorm]

Just mixed up a batch of OA, for solution B the formula specifies 200g sodium carbonate (anhy) I have washing soda crystals. According to the darkroom cookbook in the conversions section if the formula specifies sod. carbonate (anhy) And you have sod. carbonate crystal you should multiply the specified amount by 2.7. This gave me 200g sod carbonate (anhy) x 2.7 = 540g of sod carbonate (crystal). So I gradually mixed 540g of the crysttal in room temperature water, it has taken an eternity to get the sod. carbonate into solution. I have been stirring for ages, I then transferred the solution into 2 one liter bottles and did a gentle "Indian Club" workout. My shoulders have loosened up great but my B solution still looks cloudy :-( Is the 462g ever going to fully go into a clear solution or have I got the amount wrong? What should the ph of bath B be? With a simple litmus paper test mine is reading ph11 or more (my papers only read to ph11).

Problem solved I had mixed the sod. carbonate with my lime scale contaminated tap water, this caused the milky precipitate. I have now mixed part (b) with laboratory grade sodium carbonate (anhy) with deionised water; it took less than 5 mins of stirring. At least I had a good work out and I did learn not to mix the stock solutions formulas with my hard tap water.

[ibabcock]

THIN NEGATIVES -I've mixed 2 batches and double checked the recipe I get nothing but thin negatives on my 4 separate tests this weekend. 2 years ago it worked very nice. Everything mixed from powder using the potassium versions, Part A dosed with pipette. Tried from 9-15 minutes at 68 degrees F and only 1 strip of film had a black leader, the others had translucent foggy leaders. With a curves adjustment the negs scanned very high contrast - black, white and only one tone of gray. I don't know if I should try the sodium variants or drop it and go to one of the other staining developers.