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  1. #1
    JackRosa's Avatar
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    Sellective Latent Image Bleaching

    I just developed my first negative (after 27 years developing negatives) using selective latent image bleaching. I had tried compensating development, super-dilueted-developer development, staining developers,.... this technique is a winner!
    Jack Rosa

  2. #2
    roy
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    Hello Jack. For the uninitiated, like me, can you tell my why you adopted this method and what you were trying to achieve. I gather it was successful - how ?
    Roy Groombridge.

    Cogito, ergo sum.
    (Descartes)

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    Quote Originally Posted by roy
    Hello Jack. For the uninitiated, like me, can you tell my why you adopted this method and what you were trying to achieve. I gather it was successful - how ?
    Roy, this is also known as the Sterry method. David Kachel called it Selective Latent Image Manipulation (SLIMT) and wrote an article in PT many years back. In a nutshell, while bleaching after development increases contrast, bleaching
    before development decreases contrast, and it is a useful technique to have when the contrast range is too big.

    It can be used on paper as well as negatives.

    I preferred to use this on paper when I wanted more "punch" in the print and did not want the shadows blocked up. The problem I have with using this technique with the negatives is that it is not a quantifiable technique. Small variations can make a big difference and the results are not consistent, at least from a sensitometrically point of view.

    What you do is, before you develop the negative or paper, you place it on a very dilute solution of potassium ferricyanide (0.01 to 0.03 %) and then you let it sit in the solution for a little while. What this does is selectively bleach the areas that have more exposure, in the case of negatives, the highlights, in the case of prints the shadows. you then wash it and place it on the developer and continue as normal. Of course all this has to be done in the dark.

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    Jorge

    This method sounds quite interesting, my question to you would be , - Is the pre bleaching affecting the blacks.
    or are you able to hold a believable Dmax with this method???

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    Quote Originally Posted by Bob Carnie
    Jorge

    This method sounds quite interesting, my question to you would be , - Is the pre bleaching affecting the blacks.
    or are you able to hold a believable Dmax with this method???
    Which part are you talking about? pre bleach on the print?. Yes you are able to hold a beleivable black after bleaching on the print, remember you are over exposing the black to the max, with the pre bleaching you "take away" some of that exposure to get separation.

    OTOH remember you dont need to have the maximum Dmax to make it "look" black. In pt/pd the most I have heard people get is 1.5, in my case it is usually in the 1.35 to 1.4 range, yet when you see the prints it looks black...It is all in the tonal relationships.

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    Use of slective latent image bleaching.

    Prints: You may have a print with the shadows being overly black. This will allow the blacks to be controlled to the depth you desire. You mave have a print that will print satisfactorily on grade 2 but that you wish to have more highlight contrast. You could print the negative on any higher contrast grade paper and thru this technique reduce to blacks to what you had previous obtained. If act you could use grade five paper and have the resulting highlight contrast that is ordinary for grade five paper and the shadows could be bleached back to less than a grade 1. It is a very useful technique for printing.

    Film: You may be taking a photo of a scene that has far more contrast than you wish. If you develop, for example to n-3 you may end up with very muddy tones. Since the bleach affects the greatest density the most you can bring the highlights way down without the muddiness. This technique is also very usable on high contrast films that you wish to use as a continous tone material.

  7. #7

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    There is a good article on SLIMT with a picture
    of a naked girl at www.unblinkingeye.com. Dan

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    Jorge

    thankyou
    I was talking about prints,
    I do agree, as long as our eye discerns it as black it works. I am going to try this technique

  9. #9
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    Quote Originally Posted by dancqu
    There is a good article on SLIMT with a picture
    of a naked girl at www.unblinkingeye.com. Dan
    Here's a link to the article .
    Cheers!

    -klm.

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    To: Ken

    Ken: Thank you for providing the ling to Ed Buffalos's article on Latent Image Bleaching. By the way, I visited your website and want to congratulate you on your work.

    I noticed <on your site> you indicate that you use HC-110 to develop some of your negatives. I used HC-110, mostly solution B, to develop my 8x10 negatives for a long time with very good results. When I tried Rodinal 1:25 with HP5+ and 1:50 with FP4+ I immediately switched. Another developer that yiedls excellent results is PMK <pyro> 1:2:100.

    Cheers.
    Jack Rosa

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