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Thread: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everything

  1. #11

    Join Date
    Sep 2011
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    San Francisco
    Posts
    92

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    Thank you for posting this information. I am interested to experiment with this technique. I think I have already purchased the bleach kit from the PF.
    Are there any sample images from this process posted?

  2. #12

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    Hi,
    Though the kit has Photographer's Formulary on the label, they are not selling it. They are only packaging it for Freestyle. So, you can't have bought it from PF.
    There are no sample images. Sorry. This group of techniques has already existed for more than a quarter century and is therefore well proven.
    David Kachel
    www.davidkachel.com
    Author: "21st Century Dry Film Polymer (Direct-to-Plate) Photogravure

  3. #13

    Join Date
    Jan 2019
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    196

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    I've used David's technique for bleaching back silver prints before developing. Over the years people have stated that it wasn't necessary, but I don't argue with them since they probably never tried it. I don't need to SLIMT often, but it saves the bacon at times making something difficult much easier. I'm looking forward to reading the update. Thanks.

  4. #14

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    Quote Originally Posted by PRJ View Post
    Over the years people have stated that it wasn't necessary...
    I suppose it isn't "necessary", but neither are shoes. However, BOTH are damned convenient!! ;-)
    David Kachel
    www.davidkachel.com
    Author: "21st Century Dry Film Polymer (Direct-to-Plate) Photogravure

  5. #15
    Bill
    Join Date
    Oct 2017
    Location
    College Station, TX
    Posts
    75

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    Hi David. My apologies if you covered this in the text and I just didn't comprehend it, but I had a thought. In the second to last section, you covered extended development of film treated with SLIMT, and said that the film can go back to its untreated density. Are there any variations on this that can lead to increased effective film speed without the associated contrast enhancement of traditional extended development? Basically, do your SLIMTs have the proportionally inverse effect of extended development, where treating the film and then extending its development will effectively cancel one another out in terms of film speed? Or do they act at different rates, so that extended development of a SLIMT treated negative will result in increased film speed with lessened (or, I suppose, heightened) contrast?

    I am generally very bad at explaining things, so I hope that this makes some amount of sense.

    On another note, I greatly appreciate your effort in writing this document, and releasing it for free. I look forward to trying it.

  6. #16

    Join Date
    Jun 2014
    Posts
    2,084

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    I gave it a try last night for fun, using some very old Brovira paper and a negative that was a bit too contrasty. To my surprise, I found that I need to dilute the 10% concentrate by an amount of 1+100,000 (yes, 100k) to shave about 1.5 grades off the paper's native contrast. I did stepwise dilutions starting from the suggested 1+1000 in Kachel's paper, but this proved to be way too strong, and the effect seemed to follow a more or less linear decrease with exponentially higher dilutions. I went up to 1+200,000 which still yielded a significant decrease in contrast compared to the untreated paper.

  7. #17

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    Quote Originally Posted by Fagrid View Post
    Hi David. My apologies if you covered this in the text and I just didn't comprehend it, but I had a thought. In the second to last section, you covered extended development of film treated with SLIMT, and said that the film can go back to its untreated density. Are there any variations on this that can lead to increased effective film speed without the associated contrast enhancement of traditional extended development? Basically, do your SLIMTs have the proportionally inverse effect of extended development, where treating the film and then extending its development will effectively cancel one another out in terms of film speed? Or do they act at different rates, so that extended development of a SLIMT treated negative will result in increased film speed with lessened (or, I suppose, heightened) contrast?

    I am generally very bad at explaining things, so I hope that this makes some amount of sense.

    On another note, I greatly appreciate your effort in writing this document, and releasing it for free. I look forward to trying it.
    Fagrid,
    My apologies for the late response. I just can’t seem to force the software here to send me notices of new posts.
    Extended development after bleaching does not / should not, restore the original (potential) characteristic curve. Remember that latent image bleaching works more efficiently on areas of heaviest exposure. It all depends on the film and developer of course and should vary substantially with variations in both. But extended development should result in the establishment of a moderate midtone bump and a slight shoulder. The end result of an experiment using a standard SLIMT with normal development on one negative and a stronger SLIMT with extended development on another, should result in two negatives with roughly identical density ranges but different shaped characteristic curves, the latter having stronger midtones and softer highlights than the former.
    However, my experimentation with this particular application of the SLIMT techniques thus far has consisted of simple ballpark guesses when I have wanted to use it, and no quantitative measurement. My guesses have been quite accurate and I am basically lazy. It is an area wide open for fresh eyes. ;-)

    As for film speed, yes, extended development should provide a slight boost depending on the degree of additional development and the developer used. Maybe half a stop at best.
    David Kachel
    www.davidkachel.com
    Author: "21st Century Dry Film Polymer (Direct-to-Plate) Photogravure

  8. #18

    Join Date
    Sep 1998
    Location
    Oregon now (formerly Austria)
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    3,495

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    David,

    Thanks very much for this. I've been using the techniques you outlined originally, specifically for contrast reduction of B&W films, with great success for years now. I'm looking forward to reading the update.

    Best,

    Doremus

  9. #19

    Re: New FREE paper on SLIMT contrast reduction for B&W and COLOR, film, paper, everyt

    Doremus, thanks.
    Please pass the word whenever you can. So many newcomers have no idea.
    David Kachel
    www.davidkachel.com
    Author: "21st Century Dry Film Polymer (Direct-to-Plate) Photogravure

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