Who has tried SLIMT?

[Steven Ruttenberg]

I am thinking of trying it and comparing to 2 bath Pyro. I t also will work on color neg so that is something that is appealing.

We here would I get the chemicals needed?

Any examples of SLIMT people could post up next to normally processed non-SLIMT examples

[ic-racer]

Maybe best for color negatives, since contrast control is not so easy with that medium. With the advent of high-quality paper of varying grades in the 1970s, B&W contrast control during print making exceeds the contrast control available when printing color negatives.

[Pere Casals]

You need Potassium Ferricyanide, this is $10 for 100gr at ebay... it's used at very low concentration, but read well the safety sheet, as always.

Here you have information about it: http://www.davidkachel.com/assets/cont_pt3.htm

There he says "water bath development, curtailed development time, high dilution compensating development, and two–bath development — are, in my opinion, either obsolete, unwieldy, or both. They need to be replaced. Films have changed drastically over the years and they simply do not respond to these techniques the way they once did."

I don't agree with that, all those techniques are working this 2018 pretty well. Every modern film would need to adjust those techniques to the particular film, of course.

And of course he omits other techniques, like formulating the developer you want. For example with POTA developer you may obtain compression ranging 20 stops. POTA was designed to shot nukes exploding.

182930


Anyway I think it would be very interesting to test SLIMT pre-bleaching. I was wanting to do it. I'd recommend you do it by calibrating the film-development by making (as usual) a contact copy of the stouffer wedge on film and drawing the plots. If you do it please post the graphs.

[Pere Casals]

Maybe best for color negatives, since contrast control is not so easy with that medium. With the advent of high-quality paper of varying grades in the 1970s, B&W contrast control during print making exceeds the contrast control available when printing color negatives.

Racer, yes... but when we get a contrasty BW negative with densities exceding 2.5D we are in trouble, if we want to get a sound optical print... If wanting to scan and printing it digitally then we have no problem, but for an integral optical workflow better if we nail the negative.

[Steven Ruttenberg]

You need Potassium Ferricyanide, this is $10 for 100gr at ebay... it's used at very low concentration, but read well the safety sheet, as always.

Here you have information about it: http://www.davidkachel.com/assets/cont_pt3.htm

There he says "water bath development, curtailed development time, high dilution compensating development, and two–bath development — are, in my opinion, either obsolete, unwieldy, or both. They need to be replaced. Films have changed drastically over the years and they simply do not respond to these techniques the way they once did."

I don't agree with that, all those techniques are working this 2018 pretty well. Every modern film would need to adjust those techniques to the particular film, of course.

And of course he omits other techniques, like formulating the developer you want. For example with POTA developer you may obtain compression ranging 20 stops. POTA was designed to shot nukes exploding.

182930


Anyway I think it would be very interesting to test SLIMT pre-bleaching. I was wanting to do it. I'd recommend you do it by calibrating the film-development by making (as usual) a contact copy of the stouffer wedge on film and drawing the plots. If you do it please post the graphs.

I did read it and it is part of why I am asking about this interesting technique, he wrote it like 20 plus years ago.

[Steven Ruttenberg]

One thing I have found is that if you expose your digital image same as your film image (to save the shadow details) then your use of grad nd filter is all but a requirement. Unlike film, there is no latent image to develop or bleach out or whatever. Once your highlights hit zone x or "blow" out, that is it, no getting info back. But with film it seems that is not the case and if you use an grad nd filter, you more than likely can pull all the detail you want out of highlights and have good shadow detail. Any additional advice would be appreciated. Once I have tried slimt and 2-bath, I may try the other techniques.

Down the rabbit hole I go further!

I liken developing film as the analog version of a raw converter, what you do developing will forever bake your recipe into your image so better get it right.

I am going to try slimt on color and bw, and also try the 2 bath on bw and compare the images to each other including to the same image set developed "normally" (no special techniques, just like sending to Walmart back in the day). Just need to find a scene to photograph that will provide lots of contrast with a range of 15 or more stops between shadows and highlight. Would be good with 20 stops.

I believe film can still outdo digital for range of stops, no matter what Nikon, Leica, Canon, etc say.

[Pere Casals]

I did read it and it is part of why I am asking about this interesting technique, he wrote it like 20 plus years ago.

Well, near 30 years ago.

Speaking about sensitometry, I see something relevant in that SLIMT curve:

182932

There is a contraction with no speed loss, as the toe remains the same in that plot, after the contraction.



While if shortening development then the contraction implies a modification in the toe, and in the speed:

182933


My interpretation is that we can do the same with SLIMT than with a N- , but with the N- we have that speed loss. And this can be important when we value film speed.

So, from the graphs, it can be interesting to calibrate SLIMT vs regular N- in side by side conditions. At least SLIMT is quite straight, just a short FC diluted bath before development, with no rinse in the middle... so no reason to not test it.

[Ken Lee]

For example with POTA developer you may obtain compression ranging 20 stops. POTA was designed to shot nukes exploding.

With only 2 ingredients, the formula for POTA developer is very simple: see https://www.digitaltruth.com/products/photoformulary_tech/Phenidone%20Extended%20Range%20Developer%20(POTA)%20[01-0070].pdf

Given that Kodak TechPan is no longer manufactured, what other films are suitable ? Are there discussions and illustrations on the web ?

Thanks !

[Pere Casals]

POTA developer Given that Kodak TechPan is no longer manufactured, what other films are suitable ?

Thanks !

Ken, Adox CMS 20 (rebranded AGFA COPEX). Also made in 4x5 sheets.

I guess you know it... This is an amazing (and pain to use it) film (microfilm, in fact) reaching 800 lp/mm preformance, outresolving any regular glass. POTA can substitute Adotech developer.

Also POTA can be used with any film when we have extreme contrast.

There is a possibility I want to experiment, this is starting development with POTA and developing until a certain point, then rinsing well with water and finishing development with another developer, say Xtol.

In that way without mixing the chem of the two developers we can obtain an adjustable middle point between the effects of the two developers, as POTA is extremly compressing.


Some links I had saved...

POTA on Agfa COPEX Rapid:

https://www.flickr.com/photos/62756870@N02/6475695215/in/photolist-5f6MFj-4kwzSG-3ricWw-aSeCzv-avNUsM-aiVQYF-awqf6b-awqTW9-awnCYT-aSgiQk-awntjn-awqiaw


Kodak 5369 (date code 1984) shot at asa 20 developed in POTA

https://www.flickr.com/photos/7144584@N03/6253636889/in/photolist-awBwnF-dPfcZc-suSgSv-brJ3ju-dS8nRW-dPvZG8-dXwtVU-s6wyrH-s8qcDc-dNR9zD-dSn6tL-dREsRF-2734jww-dRBKpn-dSsLZc-spoyYS-dPvZD4-AfzUrv-dSi3aU-dSsLPV-dRHiT1-zSkSYK-cY3nZf-ouCR6v-dSR5Mv-awqf6b-dRuZas-Abgj9w-aSgiQk-dSR5JM-dRBK7K-Abgjpm-24miWU7-sa6HAv-dSi3eh-dRxnBG-7jMyZz-awntjn-dS8nVb-dSSEKy-dTkvQj-C2w1AF-BZdmoA-dSWWqa-BZdkFJ-Bi7Sct-dRpqjM-BZdniS-odbufQ-5Yuiqi


RX in POTA:
https://www.flickr.com/photos/neelin/4150728563/in/photolist-dREsRF-2734jww-dRBKpn-dSsLZc-spoyYS-dPvZD4-AfzUrv-dSi3aU-dSsLPV-dRHiT1-zSkSYK-cY3nZf-ouCR6v-dSR5Mv-awqf6b-dRuZas-Abgj9w-aSgiQk-dSR5JM-dRBK7K-Abgjpm-24miWU7-sa6HAv-dSi3eh-dRxnBG-7jMyZz-awntjn-dS8nVb-dSSEKy-dTkvQj-C2w1AF-BZdmoA-dSWWqa-BZdkFJ-Bi7Sct-dRpqjM-BZdniS-odbufQ-5Yuiqi-rvPEuG-owcRdf-sgNnzo-AJEMkp-AJB7DH-ow3Pmf-tkVvtV-ssNx2e-ovNAsM-dPDuB1-5YuiJi

Same location in TX + rodinal: https://www.flickr.com/photos/neelin/3149891670/in/set-72157612127780935/


TX 35mm in POTA:
https://www.flickr.com/photos/rapidwinder/8452825121/in/photolist-dREsRF-2734jww-dRBKpn-dSsLZc-spoyYS-dPvZD4-AfzUrv-dSi3aU-dSsLPV-dRHiT1-zSkSYK-cY3nZf-ouCR6v-dSR5Mv-awqf6b-dRuZas-Abgj9w-aSgiQk-dSR5JM-dRBK7K-Abgjpm-24miWU7-sa6HAv-dSi3eh-dRxnBG-7jMyZz-awntjn-dS8nVb-dSSEKy-dTkvQj-C2w1AF-BZdmoA-dSWWqa-BZdkFJ-Bi7Sct-dRpqjM-BZdniS-odbufQ-5Yuiqi-rvPEuG-owcRdf-sgNnzo-AJEMkp-AJB7DH-ow3Pmf-tkVvtV-ssNx2e-ovNAsM-dPDuB1-5YuiJi

ORWO in POTA:
https://www.flickr.com/photos/rapidwinder/17368584371/in/photolist-dREsRF-2734jww-dRBKpn-dSsLZc-spoyYS-dPvZD4-AfzUrv-dSi3aU-dSsLPV-dRHiT1-zSkSYK-cY3nZf-ouCR6v-dSR5Mv-awqf6b-dRuZas-Abgj9w-aSgiQk-dSR5JM-dRBK7K-Abgjpm-24miWU7-sa6HAv-dSi3eh-dRxnBG-7jMyZz-awntjn-dS8nVb-dSSEKy-dTkvQj-C2w1AF-BZdmoA-dSWWqa-BZdkFJ-Bi7Sct-dRpqjM-BZdniS-odbufQ-5Yuiqi-rvPEuG-owcRdf-sgNnzo-AJEMkp-AJB7DH-ow3Pmf-tkVvtV-ssNx2e-ovNAsM-dPDuB1-5YuiJi

Here we have Anneman-Gainer developer a cousin of POTA (there are mani modification of POTA):

https://www.flickr.com/groups/84061069@N00/discuss/72157627914653801/

https://www.flickr.com/photos/carljmoss/6251435876/in/photolist-5f6MFj-4kwzSG-3ricWw-aSeCzv-avNUsM-aiVQYF-awqf6b-awqTW9-awnCYT-aSgiQk-awntjn-awqiaw

[Ulophot]

Tim Layton published an article on my SLIMT results in the issue of Darkroom Underground (quarterly) released last Spring. You can order a back copy if interested. I used Kachels’contrast-wise bleaching with HP5+ and D23, showing that SLIMT supports the lower values far better than D23 1:3 with reduced development and agitation, although the latter has lovely separation and the appearance of finer grain in enlargements from 645 negs.

I tried two-bath D-23 but found that it did not support the low values quite as well as SLIMT. I may try it again at some point, since I was using trays with lights out and no agitation in the second bath; I now use the SP-445 tank or rotary processing for my sheet film. I saw an article the other day by someone who used it successfully in rotary processing, which surprised me but I’m ready to give it a try.
I pushed the practical limits of the SLIMT combination, bringing Zone XI down to a high VIII. Further contraction is certainly possible, but additional exposure may be called is probably where large low-value areas need detail. My purpose in testing was maintaining support of the lower values.

I would not say there is no speed loss, at least at the greater contractions. There may be none at N-1 or so. Note that Katchel emphasizes very different results with different emulsions and developers.

For film, you will need some Potassium Bromide, as well, for film, to avoid fog, as Kachel describes. The cost is very low, solutions have long life, and you use only 1/3 the bromide as ferricyanide when you buy 100 grams of each.
I would add, here, that long-range-neg techniques can include print flashing and SLIMT print pre-bleaching (ferricyanide-only bleach solution), which work from opposite ends to manage range. Thus, one may compress the negative a bit less and then use one or both of these to fine-tune the print, along with the usual printing techniques.

[Peter De Smidt]

David Kachel is still active on some forums. You could always email him and ask for any updates.

[Steven Ruttenberg]

Getting lots of good information here. Definitely need to set up a rigorous test procedure to nail this. There appears to be a lot of potential here as well as the 2-bath Pyro method. I wonder if both of these techniques could be combined into one and whether or not that would by anything.

Ie, bleach first like slimt, then go to solution A of pyro,then into solution B. I wonder?

[koraks]

If considering SLIMT with C41 film, note that PhotoEngineer has warned for the potential of massive dichroic fog when ferricyanide comes into contact with the developer. So rinse very well (refresh the water a few times) between the SLIMT bleach and color developer steps.

[Pere Casals]

David Kachel is still active on some forums. You could always email him and ask for any updates.

He is a 100% digital photographer since 2009, but perhaps he remembers the analog way...

[Mark Sampson]

This sounds similar to something David Vestal called "Sterry's method" in his book about B&W enlarging. Does anyone know if the two processes are similar, or identical?

[Pere Casals]

This sounds similar to something David Vestal called "Sterry's method" in his book about B&W enlarging. Does anyone know if the two processes are similar, or identical?

Mark, yes, here Kachel explains it: http://www.davidkachel.com/assets/cont_pt3.htm

The Sterry's was made with dichromate, and provocated a remarkable speed loss.

[Mark Sampson]

Thank you, Pere, for doing the research for me. Having read through some of the documentation in Mr. Kachel's fine article, I am reminded of the title of one of the great W. Eugene Smith's college courses; "Photography Made Difficult".
And how my one-time teacher David Vestal explained that in his photography, over time, he gravitated toward images that could be recorded easily. That is, over decades of work, he (almost unconsciously) chose subjects that would look good with a fairly standard practice. Mr. Vestal did investigate Sterry's method and reported on it in his "The Art of B&W Enlarging", although he thought it (mostly) unnecessary. FWIW, he wasn't teaching the method in 1985, instead emphasizing simplicity of technique.
The SLIMT process does indeed sound like an improvement over Sterry's method... but in my own work I've seldom come across the need to handle such extreme brightness ranges. Good to know there's a way to deal with that, though.

[Pere Casals]

"Photography Made Difficult".

I found that: William Eugene Smith: Photography Made Difficult, 1989, Full Length

https://www.youtube.com/watch?v=aulz5efN2Pc

Really worth to watch it !


although he thought it (mostly) unnecessary.

Yes... if with the Sterry's we end in a straight line at the cost of speed loss, then a N contraction also does it. But if Kachel's method has no speed loss, then it has an advantage...

I imagine that this speed conservation would help night photography, as we can contract without having to extend exposure for the shadows, and thus avoiding additional LIRF. Now that Neopan is not with us...

[Steven Ruttenberg]

I found that: William Eugene Smith: Photography Made Difficult, 1989, Full Length

https://www.youtube.com/watch?v=aulz5efN2Pc

Really worth to watch it !



Yes... if with the Sterry's we end in a straight line at the cost of speed loss, then a N contraction also does it. But if Kachel's method has no speed loss, then it has an advantage...

I imagine that this speed conservation would help night photography, as we can contract without having to extend exposure for the shadows, and thus avoiding additional LIRF. Now that Neopan is not with us...

Yes, night time photography poses a quandry on how to get good shadow detail without blowing out things like street lamps and such. I might try it on that as well.

I got lucky and picked up 120 sheets of Neopan Acros 100 after it went out of production. I am not touching it until I know 110% what I am doing both taking and developing images. I do find from a little bit of using Acros and comparing to Tmax100 they are similar. I like the Tmax because its reciprocity failure is almost identical to Acros, ie, only a few seconds difference between the two and with Tmax, once you go past a certain time all you need to remember is to double you standard exposure time, which would be slightly more than Acros.

This is another reason I am interested in this technique and 2-bath. As I stated earlier, I am going to combine the two. Ie, the bleach, then into the 2-bath process and see how that goes. I will also use Tmax developer since I have it. Any suggestions on other developers? I shoot for now, Tmax, HP5, D100. Color is more or less a given.

[Pere Casals]

Any suggestions on other developers?

Mixing developers in the same bath is controversial, in fact each developer has an optimized formulation and mixing chem even can lead to explosions :). Xtol + Rodinal is a mix that has had some popularity, delivering deep blacks and IMHO working a bit like a toe cutter.

...but using two different developers in a row, if we perform a rinse in the middle, is an interesting way because we don't mix the chem, so each developer makes it's share of the job alone, and this allows to virtually combine any developers.

IMHO, in general it's not necessary to go in this way for most common jobs, because we have there plenty of developers covering many common needs, and also we can vary the dilution and formulation of developers that we can mix at home.

Anyway I think that, for some jobs, using two developers separated by a rinse is a sound way to address difficult problems. IMHO using POTA in a share of the development would be a way to adjust compression that deserves some experimentation, it's something that I had pending to try, so I'd be very happy if you try it and tell the results.

Probably the order of the developers is important, at least because of the solvent action. I thing best way to start would be making calibrations with the Stouffer and drawing the plots.

[Steven Ruttenberg]

Mixing developers in the same bath is controversial, in fact each developer has an optimized formulation and mixing chem even can lead to explosions :). Xtol + Rodinal is a mix that has had some popularity, delivering deep blacks and IMHO working a bit like a toe cutter.

...but using two different developers in a row, if we perform a rinse in the middle, is an interesting way because we don't mix the chem, so each developer makes it's share of the job alone, and this allows to virtually combine any developers.

IMHO, in general it's not necessary to go in this way for most common jobs, because we have there plenty of developers covering many common needs, and also we can vary the dilution and formulation of developers that we can mix at home.

Anyway I think that, for some jobs, using two developers separated by a rinse is a sound way to address difficult problems. IMHO using POTA in a share of the development would be a way to adjust compression that deserves some experimentation, it's something that I had pending to try, so I'd be very happy if you try it and tell the results.

Probably the order of the developers is important, at least because of the solvent action. I thing best way to start would be making calibrations with the Stouffer and drawing the plots.

I am going to order the stouffer charts as they are not expensive, even the resolution chart which I will use to adjust focus on my scanner. Much better than scratching a negative with a razor blade.

Explosion huh? Well, that would not be good! My wife would get upset if I blow up the kitchen! I tend to shoot difficult scenes, landscapes at sunset/sunrise, facing the sun, night time shots. One of my more difficult shots is of the Grand Canyon at sunset/sunrise. Very difficult to get the Canyon properly exposed to reveal its awesome detail and at the same time get the sunset/sunrise properly exposed. Even using reverse grad nds and regular grad nds doesn't help a 100%. Especially when you can have 10-20 stops of difference between darkest shadow you want details from and the big ball of fire low on the horizon with back lit clouds, etc. Another scene I shoot is back lit trees like Aspens, Oaks, etc during fall colors. You pretty much can expose for the trees/leaves and give up on the sky if it is poking thru. For this, the bleach then into developer for color neg sounds promising.

I found this for POTA, which one or both? https://www.adorama.com/l/?searchinfo=pota

I can try the following combinations

1. Standard developing (n-1 or -2) Use Tmax
2. 2-bath Pyro
3. Bleach, rinse, tmax
4. Bleach, rinse, 2 bath
5. Bleach, rinse, POTA
6. For color, bleach, rinse, develop as usual (maybe pull 1 or 2 stops)

Given each process has a unique trait, It would be interesting to figure out how to use all in a process to get each traight of developer into an image

7. Bleach, POTA, 2-bath, with rinse in between each step. Don't think throwing in Tmax would add anything, but if I get bored, why not try it.

[Ulophot]

Just a note, for any who may be interested in using SLIMT for medium or smaller formats:

The contrast-wise bleaching does increase grain, at least in combination with D23 and HP5, which is what I use. (I realize that many folks shoot slower, smaller-grained films, and use developers that may not be affected the same way.) It is not a major issue in medium format (I shoot 645). At approx. 10x enlargement, (moderately cropped 645 at 11x14), the difference when compared with a normally processed negative is discernible at arm's length or so; at 7x (about full-frame 645 at 11x14), the grain difference is insignificant, to my eye at least.
I don't know what causes the increase, but I have tested for it several times and find it consistent, varying somewhat with SLIMT dilution and time. For LF, no need to even think about it.

[Pere Casals]

Just a note, for any who may be interested in using SLIMT for medium or smaller formats...

Thanks for that feedback, it would be interesting to see how the grain structure is modified.