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Thread: Super Iron Out

  1. #11
    Rudeofus's Avatar
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    And for those who still can't make much of this MSDS: The compound "Sodium Hydrosulfite" shown in the list of constituents is better known under the name Sodium Dithionite which is a known photographic developer. Since the second developer in reversal process has to develop all the Silver Halide it can find and all Silver Halide has been exposed to strong light, it doesn't matter much that Dithionite fogs and produces poor emulsion speed.
    Trying to be the best of whatever I am, even if what I am is no good.

  2. #12
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    Quote Originally Posted by richyd View Post
    I have just got some potassium thiocyanate and will experiment with that.
    Let me know how that works out. I have some here and I have not had any success.
    Get it right in the camera, the first time...

  3. #13

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    Quote Originally Posted by Rudeofus View Post
    And for those who still can't make much of this MSDS: The compound "Sodium Hydrosulfite" shown in the list of constituents is better known under the name Sodium Dithionite which is a known photographic developer. Since the second developer in reversal process has to develop all the Silver Halide it can find and all Silver Halide has been exposed to strong light, it doesn't matter much that Dithionite fogs and produces poor emulsion speed.
    There's a fundamental difference.
    The developer reduces AgBr to Ag(0) if the silver halide grain has been exposed to light.
    Dithionite reduces AgBr in absence of light.

  4. #14
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    Quote Originally Posted by Alessandro Serrao View Post
    Dithionite reduces AgBr in absence of light.
    That's what they call a fogging developer ...
    Trying to be the best of whatever I am, even if what I am is no good.

  5. #15

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    @alessandro : " I use 10gr/lt of dichromate and 10ml/lt acid and use 3min standard bleaching time." Wow that's high concentration from the recipes I have seen. When I researched this last year I got the most useful info from 'mrred' who posts here, from his blog - My Fim Stuff - on blogspot, specifically using Foma classic and other films and my original source for the Iron Out info. He used 6gr/ltr dichromate. I use the sodium bisulphate, 55gr/ltr, acid substitute as it is easier for me to obtain.

    I have been paranoid about over bleaching. I found a thread on Apug last year fom someone quoting from a book by Haist about reversal development. I can't find the thread now maybe it is archived, but have copied the content so if you want that would be happy to email it to you. Quoting from the book he said that a dichromate bleach, 0.5% K dichromate & .5% H2SO4, should be done within one minute and time should not exceed 3 minutes.

  6. #16

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    A pure speculation: if the bleach only renders water soluble (Ag-sulfate) the Ag(0) reduced by the first developer, how can be possible to overbleach?
    In other words: is it possible that the chromic acid will render also AgBr water soluble?
    I don't think it's possible at all.
    Last edited by Alessandro Serrao; 06-20-2013 at 04:39 PM. Click to view previous post history.

  7. #17
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    Quote Originally Posted by johnielvis View Post
    Good to see that others now see the benefits of no hypo in the first developer. Results speak volumes, don't they?
    It's the first attempt that I will use no hypo. Experience has shown me that some hypo is usually required, if not for anything other than evening out the curve.

    But yes, too much hypo is usually the result in trying to make an unsuitable film usable or using a developer not up to the task. We still have choices, and the ones that use the least / none are usually the best.
    Get it right in the camera, the first time...

  8. #18

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    Quote Originally Posted by johnielvis View Post
    Good to see that others now see the benefits of no hypo in the first developer. Results speak volumes, don't they?
    However there's a thesis work "INFLUENCE OF FIRST DEVELOPER SOLVENT LEVELS ON THE INFORMATION STORAGE CAPACITY OF NEGATIVE AND REVERSAL IMAGES" By W. R. Harrison B.S . St . Lawrence University, School of Photographic Arts and Sciences Rochester Institute of Technology, Rochester, N.Y.

    that states that a silver halide solvent must be present in the first developer to obtain a higher quality picture.
    Last edited by Alessandro Serrao; 06-21-2013 at 07:36 PM. Click to view previous post history.

  9. #19

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    Quote Originally Posted by johnielvis View Post
    Well, my experience and research gives me the data to state firmly that I disagree with that. Besides, define "quality". He's got different standards for different things than I do. If you want to get down to it, some things are better off with solvant, some without solvant. No way can you make a claim one way or the other--it all depends on the application. It's just amazing how people usually always go with what's printed instead of what they're own senses tell them.
    My experience (as well as Kodak's, Ilford's, Orwo's) calls for hypo in the first dev,otherwise I cannot obtain a clead DMin.
    It's a tradeoff.
    Last edited by Alessandro Serrao; 06-22-2013 at 01:35 AM. Click to view previous post history.

  10. #20
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    There are some good points discussed here.

    When I bench a film, I get as close as I can with a non hypo'ed developer. This goes as far as using a 1:1 mixture of dektol. I get it close, and then start adding various levels of hypo. This is also why I use a stock solution of hypo and only add it at development time; the optimum levels are different with each film and I don't like to stick with one film. The thing is, hypo is a general solvent. It will remove and lower your dmax too. The right amount is important and not developing enough is counter productive. using a weaker developer (like rodinal, d76, ..etc) will yield "thin chromes" or be too fogged or just too expensive on developer use.

    Sometimes I use a selenium toner for a final bath. This helps thicken the image when you can't build up enough silver. Most traditional processes to "fix" negs still apply.

    Ideally, you want a developer with ph 10 or greater to give you the activity you need. What you need to develop negs well is not what you need to develop chromes well. I have been playing with some concoctions targeting this. So far it's good, but dektol seems to get the best results for me.
    Get it right in the camera, the first time...

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