density is the same development is different

[swmcl]

Hello.

I am stumped. My recent tests reveal that I haven't managed to change the density of negatives even though I've done three tests from 8:15 mins to 8:45mins and then 12 mins.

So ... all things being equal ... I took 6 shots in each test (6 photos can be developed at a time in a 3006). No exposure, Zone 1, Zone 5, Zone 7, Zone 9 and Zone 11.

The longer development time has increased density in the Zone 11 shot somewhat.

no exposure (fb) 0.11 ortho
Zone 1 0.17 ortho
Zone 5 0.61 ortho
Zone 7 0.86 ortho
Zone 9 1.12 ortho
Zone 11 1.3 to 1.41 ortho

Film is FP4, developer is 1:1:100 Pyrocat-HD, fixer is TF5. Film exposed for ISO 64.

Why no real change ? I was expecting a significantly greater density in the 12minute dev test but it really only went from around 1.3 to 1.41 at Zone 11.

Its as though I could leave it in the drum for any time and there would not be a significant change !

Rgds,

Steve

[Leigh]

I assume you mean FP4+.

The Ilford datasheet shows a D-max of around 1.8. Not very dense at all.
No developer will take you beyond the capabilities of the film's emulsion.

How do your mid-range values compare (ZVI, ZVII)?

Why don't you do your tests with a real developer, one that has known characteristics?

- Leigh

[Andrew O'Neill]

Yes, your zone XI should be at least 2.9 with FP4 or slightly higher. I use pyrocat-hd all the time with this film. How fresh is the developer? Are you buying it or mixing it yourself?

[swmcl]

Hi guys,

The developer and fixer are as fresh as I can get. Recently imported.

Mixed an hour or so before use and left in a stainless beaker in my water tub to stabilise the temp.

Separate syringes to mete out the quantities ...

I've tried to be as careful as possible.

Mid range values virtually identical only the Zone 11 value is different to any extent.

Leigh I did see that FP4+ is density limited in the datasheet this morning too.

Only other developer is old Accufine or Diafine ...

Does the developer simply wear out ?

Thanks for your thoughts.

Steve

[Leigh]

Developers at working strength can have very short service lives. Depends on the developer.

Diafine is a compensating developer. Acufine may be considered compensating... depends on who you ask.
I have both sitting here on my desk, and use both of them, particularly Diafine for tray development of sheet film.

What are you trying to accomplish? You seem to be flailing about with no particular goal in mind.

- Leigh

[Lachlan 717]

Did you make sure that you shook the Pyro bottles prior to developing?

Not doing so can lead to very thin negs.

[Cor]

Hi guys,

The developer and fixer are as fresh as I can get. Recently imported.

Mixed an hour or so before use and left in a stainless beaker in my water tub to stabilise the temp.


Thanks for your thoughts.

Steve

I do not think it's a good idea to mix PyrocatHD (A+ B + water) 1 hour before use, what was the colour of the developer when you poured into the tank? If it was brown(ish) it's already oxidized and not fully active anymore.

I mix the water and the B component (potassium carbonate) and let those stabilize, just before I need the developer I mix part A in and use it within a minute or so (probably overkill, but that is my routine).

good luck,

Best,

Cor

[Bruce Watson]

Did you have enough developer agent in the 3006? The Jobo tubes make it easy to use so little developer that you can easily exhaust it. Once that occurs no amount of extra development time will increase density.

[Gem Singer]

Density is a function of exposure time.

Contrast is a function of development time.

[Leigh]

Density (maximum) is a function of the amount of silver in the emulsion.

No developer on this side of the fifth dimension can change that.

Contrast is determined by density.

- Leigh

[Jay DeFehr]

Steve,

something is wonky in your test. I agree it's not good practice to let your working developer sit for an hour before use. If you want to temper it, temper the water with part B added, and then add the part A just before use. The part A will not drop the temp much, and it should return to temperature very quickly.

[Jay DeFehr]

Density (maximum) is a function of the amount of silver in the emulsion.

No developer on this side of the fifth dimension can change that.

Contrast is determined by density.

- Leigh

Leigh,

you're obviously confused about something, or several things. I suspect you pulled your Dmax figure for FP4 Plus from one curve in their data sheet, for that film developed in Ilfotec HC (1+3) for 8:00, at 68F. That curve hardly represents the film's Dmax.

Developers can change a film's Dmax, and you're sort of right, these developers do add another dimension -- image stain. The print density created by a stained negative results from silver density + stain. Pyrocat HD is a staining developer.

[Jim Noel]

My thoughts as I have read this thread:
1. You should not mix your developer until ready to use it. I usually add part "B" just before placing the film in the developer.
2. You need at least 102 ml of diluted developer (1:1:100)for each sheet of 4x5.
3. When using pyrocat hd, or any similar developer, printing density is greater than visual density
4. Only a UV densitometer will give you true readings of stained film
5. if using a non-UV densitometer, read the blue channel for a better indication of printing density.
6. you might give 2:2:100 dilution a try. This should provide greater density in the highlights.

[Gem Singer]

Leigh,

You are merely restating my premise. Perhaps I stated it too simple.

I'll restate it on a molecular level:

The more silver molecules in the film emulsion, the more sensitive it is to light (the higher the ISO). As more light strikes the film, more silver molecules become sensitized.

The longer the film is developed. the darker the exposed silver molecules become (up to their maximum capability).

The greater the difference between the darkened silver molecules and the unexposed areas of the film, the greater the contrast.

[Leigh]

The longer the film is developed. the darker the exposed silver molecules become (up to their maximum capability).
That's right... "up to their maximum density". That's exactly what I said in post #10 above.

If you grossly over-expose a sheet of film (leave it lying on the kitchen table for a day), then grossly
over-develop it (10x normal time, with constant agitation), you will achieve some density that is the
maximum the film can achieve under any conditions. That was my point.

Of course this addresses only the operation of real developers, not "staining" developers.


The greater the difference between the darkened silver molecules and the unexposed areas of the film, the greater the contrast.
That's correct, by definition. And the achievable contrast is limited by the film's inherent Dmax.

- Leigh

[IanG]

I think Jim Noel might have a point about the volume of developer being used. Back in the 1950's when Ilford where working on Replenishable PQ version of ID-11/D76 they did some analysis to see just how much of each compund was being used up. Their final product Autophen needed far less replenishment than ID-11/D76 because unlke MQ developers PQ ones are less affected by build up of bromides etc.

The bottom line is the amount of developing agent present in the dilute developer if these get used up and drop below an effective level increasing the devolpment time has far less effect on the highlight areas of the film (near to the Dmax) but unused developer in the shadows and to a lessre degree the midtone will continue to develop.

Think of it like a two bath process once the level of dveloping agents in the solution drop, the alkalinity will continue to dvelop in arae where the developer has diffused into the emulsion but not exhausted. The term compensating developer is used to describe the effect.

Ian

[Jay DeFehr]

My thoughts as I have read this thread:
1. You should not mix your developer until ready to use it. I usually add part "B" just before placing the film in the developer.
2. You need at least 102 ml of diluted developer (1:1:100)for each sheet of 4x5.
3. When using pyrocat hd, or any similar developer, printing density is greater than visual density
4. Only a UV densitometer will give you true readings of stained film
5. if using a non-UV densitometer, read the blue channel for a better indication of printing density.
6. you might give 2:2:100 dilution a try. This should provide greater density in the highlights.

Jim, it's better to add the part B alkali first (counter-intuitive, I know). The part A will oxidize, even without part B, and while mixing the part B into the solution. Also, for most accurate sensitometry, the densitometer light should match as closely as possible the spectral sensitivity of the printing process. For UV processes, that would be UV, but for graded papers, Blue is closer. Just because the UV filter will read more stain density, doesn't mean it's a more accurate reading.

[swmcl]

Thanks fellas.

OK. I did mix parts A and B probably up to one hour before use. Yes I can stabilise beforehand.

- I'm not getting uneven development. I am using 450ml of developer solution in the tank for 6 negs. That's 75ml per neg. Jobo has 50ml per 4x5 sheet and a minimum total of 210ml in the tank.
- Jim says 102ml per sheet ... I can't see where that is written so I assume it is borne from experience - which is probably worth more than any book ! Ian ... thanks ... it is looking as though I'm depleted.
- The developer looked pretty clear when it went in. It might have been slightly tanned but nowhere near the colour of when it came out of course.
- Yes I have the 361T UV densitometer. No I am not doing the wet darkroom thing. I will go digital after development. I have taken readings at both the UV settng and the Ortho ? setting. The point is that it isn't a very strong CI.
- Rotation by hand in a couple of inches of temp. regulated water is possibly no more than 6 rpm.
- Thanks Leigh I do see the FP4+ curve in the datasheet and am now wondering what film will give me a higher Dmax. I believe the datasheet is correct. FP4 just won't go high.
- My 'goal' is a nice straight line and a reasonably solid Dmax. At present I'm getting a VERY straight line out to Zone 16 it seems without any great Dmax. I'd rather have only 12 Zones and a Dmax at Zone 12 of 2.4. So yes I'm chasing a bit steeper CI.
- I'll take it from Jay that the Part B goes in first ?

Guys,

I think FP4 just wont go very high in terms of Dmax. That said, something should have changed by going from 8:15 to 12 mins.

Also, it looks as though I need more solution and also perhaps go for the double strength of 2:2:100. I think 102ml is a bit accurate !! Could we settle for 100ml ?!?! Its a nice round figure.

The problem there is that 100ml for a 4x5 sheet would equate to a 175ml per sheet of 5x7 and hence 1050ml for the tank. The Jobo limit is 1000ml ...

At this rate I'm going to be using all my new film on testing !!! 18 sheets already.

I'll now go away and run a test with 600ml in the tank of 2:2:100 with Part B in first and Part A in just before development. I think I'll shoot at ISO 64 and develop for 9 mins.

Thanks guys.

[ic-racer]

Hello.

I am stumped. My recent tests reveal that I haven't managed to change the density of negatives even though I've done three tests from 8:15 mins to 8:45mins and then 12 mins.

So ... all things being equal ... I took 6 shots in each test (6 photos can be developed at a time in a 3006). No exposure, Zone 1, Zone 5, Zone 7, Zone 9 and Zone 11.

The longer development time has increased density in the Zone 11 shot somewhat.

no exposure (fb) 0.11 ortho
Zone 1 0.17 ortho
Zone 5 0.61 ortho
Zone 7 0.86 ortho
Zone 9 1.12 ortho
Zone 11 1.3 to 1.41 ortho

Film is FP4, developer is 1:1:100 Pyrocat-HD, fixer is TF5. Film exposed for ISO 64.

Why no real change ? I was expecting a significantly greater density in the 12minute dev test but it really only went from around 1.3 to 1.41 at Zone 11.

Its as though I could leave it in the drum for any time and there would not be a significant change !

Rgds,

Steve

My take on this is that the developer is exhausted during the processing run. Beating a dead horse (increasing time) won't help.
Try more developer molecules per square inch of film.

[Brian Ellis]

Thanks fellas. . . . At this rate I'm going to be using all my new film on testing !!! 18 sheets already. . . . Thanks guys.

I once went through a 25 sheet box of APX film doing tests. Shortly after that I quit doing it myself and paid The View Camera Store $30 or so to do it for me. Not only did I save time and money I got far more information from them than I got doing it myself.

There's certainly something to be said for the learning experience of doing your own tests. But only up to a point and beyond that point it's just rote. If you've used 18 sheets so far and are still going I think you've reached that point and you're ready to let someone else do the tests while you go out and make photographs.

www.viewcamerastore.com, go to "BTZS Products," then "testing service."

[Leigh]

- Thanks Leigh I do see the FP4+ curve in the datasheet and am now wondering what film will give me a higher Dmax. I believe the datasheet is correct. FP4 just won't go high.
My standard film (4x5) is Fuji Acros. I love it.

There's no shoulder on the published curve, just a straight line going up to the right.
Don't know what its Dmax is. I've never blown a highlight. Like the Bunny... It just keeps on going.

- Leigh

[Michael Kadillak]

The developer mixed and left to sit that long is exhausted and incapable of sufficient developer activity. I tried to run two sheet film runs after just mixing Pyrocat HD and noticed that the second batch was already showing signs of developer exhaustion after only 15 + minutes. Mix the A and B just before use and you will be just fine. Pyrocat HD is a one shot developer.

[polyglot]

You say it went from 1.3 to 1.41, which is an increase of 0.11, i.e. 28% more density. That's not a surprisingly-small increase to me, especially if there's extra density in the silver and not much extra density from staining, resulting in a small apparent increase in the total density.

Caveat: I don't do pyro.

[Leigh]

Steve...

Forgive me for getting back to basics, but... WHY are you obsessed with Dmax?

In over 50 years of shooting I've never once cared what Dmax was for any film.

I shoot negatives that yield excellent prints on "normal" paper. That's all I care about.

Am I missing something?

- Leigh

[swmcl]

@Brian ... I appreciate your thoughts but they (the thoughts) make me feel bad !! Sorry I can't post any images today of any worth. Just ones of a shed door close up and out of focus ...

@Leigh. I am designing a fully automated film processing setup at the moment. If I choose to use a temp sensor that varies 0.1 volt for each degree rise in temp that would not be as sensitive as one that had a variance of 2 volts per degree. My A/D converter gives me more meaningful results if the variance is larger.

The same holds for scanning. If I scan a negative then I should prefer to have that negative giving me information right across the scanner's range rather than over a limited amount of the range. I believe it would produce a banded histogram if one were scan over a limited range then expand it in PS ? (I haven't got to PS yet ....)

Besides, I prefer images with some contrast. Some images I've seen on this site developed in Pyro don't have as much punch as I like and I thought it was the way the photog had set it not because Pyro couldn't deliver much more contrast !

Guys, I didn't realise Pyro was so oxidisation sensitive. It is rather disappointing because of it. More points to the thought of having nitro or argon injection but that's another story eh !!

I've got a feeling that I'm still going to suffer from the oxidisation issue even at 4 or 6 rpm and immediate mixing before use.

What's LC29 like ? ...

[Leigh]

Steve,

I'm sorry if this sounds unflattering, but I believe in speaking my mind.

This is so bizarre I don't even know where to start. You sound like a high school kid who's got this great idea in his head.

Have you ever done any analog circuit design? Doesn't sound like it.

Have you ever designed a real-time control ssytem? Doesn't sound like it.

Have you ever printed any real photos? Doesn't sound like it.

- Leigh

[IanG]

The developer mixed and left to sit that long is exhausted and incapable of sufficient developer activity. I tried to run two sheet film runs after just mixing Pyrocat HD and noticed that the second batch was already showing signs of developer exhaustion after only 15 + minutes. Mix the A and B just before use and you will be just fine. Pyrocat HD is a one shot developer.

My experience with Pyrocat HD and other Pyrocatechin based developers is that the keeping properties of the stock solution (when not using glycol or similar) or the working solution are governed by the efficacy of the Metabisulpite in the solution. The governing factor is how fresh the Metabisulphite is when the solution is made up, we depend on the disolved free SO2 from the metabisulpite to prevent the Pyrocatechin oxidising.

With fresh Metabisulphite the stock solution will last around 18 months (made up in water) in a glass/plastic bottle even partially full for the latter part of the time. As soon as the Metabisulphite has completely broken down to form sulphite the developer begins to oxidise. (Plastic bottles must be high density plastic as lower density plastcs allow oxygen to permeate throgh their wall - enough for Pyrocat to begin to oxidise in a couple of months)

In solution the Carbonate reacts with the metabisulphite to form sulphite but this isn't immediate so again the efficacy of the metabisulphite is a crucial factor. With Pyrocat it's easy to spot oxidation as the solution begins to have a blue-green tinge.

It should last 15 minutes with no ill effect once made up to working strenght, sometimes a bit longer, I've had no problems after about 30 minutes.

Ian

[swmcl]

Well ! I do apologise if what I've said was offensive.

[Brian Ellis]

@Brian ... I appreciate your thoughts but they (the thoughts) make me feel bad !! Sorry I can't post any images today of any worth. Just ones of a shed door close up and out of focus ....

I'm sorry if my suggestion that you try using The View Camera Store to run your tests made you feel bad. I don't know why it would but since it apparently did I apologize. I certainly didn't intend to make you feel bad. I'm also not sure why you mention posting images, I didn't say anything about that. But good luck with whatever you end up doing in the way of film and processing.

[swmcl]

Brian,

Absolutely no offense taken. I certainly appreciate what you're written and choose to 'finish the job' of testing that is.

Communication between humans is a complex thing isn't it !

Best,

Steve

[polyglot]

@Leigh. I am designing a fully automated film processing setup at the moment. If I choose to use a temp sensor that varies 0.1 volt for each degree rise in temp that would not be as sensitive as one that had a variance of 2 volts per degree. My A/D converter gives me more meaningful results if the variance is larger.

Water-bath temperature control is a solved problem with 0.1C trivially achievable with about $50 of off-the-shelf control hardware. Which has nothing to do with density.


The same holds for scanning. If I scan a negative then I should prefer to have that negative giving me information right across the scanner's range rather than over a limited amount of the range. I believe it would produce a banded histogram if one were scan over a limited range then expand it in PS ? (I haven't got to PS yet ....)

Not so fast... If you scan with insufficient bit depth (not enough to represent the dynamic range in the final image), you get quantisation (banding). Even a crappy scanner these days gives about 13-14 bits of real dynamic range (4.0D), which is more than enough to represent all of the tonal information in a B&W negative and more - see below. Your limiting factor in quality is not quantisation in digitisation, it's grain in the film, flare and softness from scanning misfocus. Increasing the development to get more density range will reduce an irrelevant error at the cost of magnifying the dominant error (grains and clumping).


Besides, I prefer images with some contrast. Some images I've seen on this site developed in Pyro don't have as much punch as I like and I thought it was the way the photog had set it not because Pyro couldn't deliver much more contrast !

This is a digital image-processing mistake very common on LFPF and APUG where people seem to think that if there's information in the negative, it must make it to the final image. The problem is that the film and scanner will often represent 12+ stops of dynamic range, so you end up with a file with 12 stops in it. People then put the black & white points at the extremities of this range, save it as a jpeg with no gamma and woops, the contrast is now about 4 grades too low and the image looks like grey boringness regardless of what was present in the negative. Cranking up the development will not solve the problem because the problem is not the development, it's the digital post-processing and interpretation of the negative.

While Leigh didn't put it constructively at all, I think he's right. You're grasping at the wrong things due to weird partial understandings; you're aiming for gold-plated processes that might get a skilled practitioner that extra 1% of quality because they know exactly how to tailor their process to get a desired result, whereas you don't seem to have the basics of exposure and development down. Pyro, funky development machinery and even sensitometry are IMHO a distraction at this point.

There are no magic bullets. Do normal development until you know exactly what it will look like. Ignore dmax and aim for a particular contrast-index if you're going to do sensitometry at all, or at least do BTZS instead of faffing about and making it up. Use simple and foolproof developers (stuff that doesn't oxidise or have weird failure modes) while you're still learning. A well-executed print in basic materials will be far, far better than a mediocre print from the fanciest materials. Most of the time, you won't even be able to tell what materials were used because technique is the dominant factor.

[swmcl]

Sorry.

To be honest, I'm tired of this thread now. Things have gone too far.

Over and out.

[Bill Burk]

Sorry.

To be honest, I'm tired of this thread now. Things have gone too far.

Over and out.

Haa, I came here to see how it worked out and find it flamed out...

Did you find you had developed to completion? Or insufficient developer stock?

I always thought of Pyro as a developer for long-scale Subject Luminance Ranges where you need to hold down the D-Max... Maybe it's just "doing its job"?

Even though the silver density may not be above 1.4, what's the silver + stain equate to? You can find out by contacting a standard gray scale next to a developed film gray scale and see which light patches match on the print.

[Stephen Benskin]

Personally, I think a time / gradient curve would go a long way in helping to track down the problem. You'll be able to see trending which will help determine if there is fault in the test or simply the way the film / developer combination works.

[Stephen Benskin]

Here's an example of two CI / Time curves. Both represent 5 sheets of TMX 4x5. One set is developed in PMK Pyro and the other in Xtol.

74645

[Jay DeFehr]

Stephen,

That PMK curve is surprising, to me. How are you determining contrast? It's been several years since I tested PMK, and I used TMY, but I remember getting much higher contrast.

[Stephen Benskin]

Jay,

My program uses a variation of Contrast Index.

[Jay DeFehr]

Jay,

My program uses a variation of Contrast Index.

Stephen, I'm aware of your considerable expertise in sensitometry, which is why your results are so interesting to me. How are you accounting for the image stain in determining contrast?

[Stephen Benskin]

Stephen, I'm aware of your considerable expertise in sensitometry, which is why your results are so interesting to me. How are you accounting for the image stain in determining contrast?

These tests were part of a project Kirk Keys and I were working on. We wanted to see if the projected densities from a Pryo negative matched the projected densities of a non-staining developer like Xtol. All the negatives were read with white, blue, and green light. The examples are white light. Although we never finished the project, we did test a number of different films. I would make the sensitometric exposure and Kirk would process the film. My McBeth densitometer had old uncalibrated color filters, so Kirk read the film, and I plotted them using my program. The next step was to carefully print negatives with identical CIs and determine if the resulting reflection densities followed tone reproduction principles or if the staining created a compensating effect. In other words, you can blame Kirk for the processing.:)

But this is moving away from the subject at hand and that is different film / developer combinations will create different development velocities. Without using a tool like a CI / Time curve it is possible to confuse a naturally occurring condition of a low development velocity combined with a low gamma infinity with a mistake in processing. It's definitely an option to consider for the type of results Steve has described.

[Jay DeFehr]

Thanks, Stephen-- that (white light reading) partially explains the discrepancy. I think the most accurate way to test staining developers is by reading prints made from stained step wedges. I realize this imposes certain limitations, but it avoids certain inevitable inaccuracies, too.

[Stephen Benskin]

Jay,

To be thorough, here's a comparison of the TMX PMK test read with white and blue light.

74895

And here's a CI / Time curve with a low development velocity and is not from a staining developer. APX 25 in Xtol.

74896

To address Steve's situation, there isn't a consistent correlation in the percentage of development time to density increase. Different film / developer combinations will produce different development rates. A number of conclusions can be drawn from a flatter CI / Time curve. The most obvious is that development doesn't have to be as precise. Development can vary by a few minutes without adversely effecting the contrast. This can be extremely beneficial for someone without the ability to test, or perhaps for a beginner. A steeper CI / Time curve indicates a greater change in contrast with development time and will require a higher degree of control in order to produce consistent negatives.