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.




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.




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:



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:




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/627568...-awntjn-awqiaw


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

https://www.flickr.com/photos/714458...-odbufQ-5Yuiqi


RX in POTA:
https://www.flickr.com/photos/neelin...-dPDuB1-5YuiJi

Same location in TX + rodinal: https://www.flickr.com/photos/neelin...7612127780935/


TX 35mm in POTA:
https://www.flickr.com/photos/rapidw...-dPDuB1-5YuiJi

ORWO in POTA:
https://www.flickr.com/photos/rapidw...-dPDuB1-5YuiJi

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

https://www.flickr.com/groups/840610...7627914653801/

https://www.flickr.com/photos/carljm...-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.