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  1. #21
    pierods's Avatar
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    Quote Originally Posted by Rudeofus View Post
    You seem to enjoy photochemistry and home brewing but lack the basics to formulate a developer. Learning is always a good thing and I recommend you dig through some photographic literature. Here is my recommended reading list:

    • Recipe selection on APUG and digitaltruth for a brief overview of common formulas. Don't get carried away with these recipes, quite a few of them are outdated and won't work as advertised with new film stock.
    • Mees, The Theory of the Photographic Process. This book is very old (think Forties) but very informative, and best of all, you can download it legally and for free.
    • Haist, Modern Photographic Processing. Despite its much newer date of publication, it offers quite outdated info on many subjects. Kodak would have stomped heavily on Haist's toes if he would have published more recent discoveries it seems. Still, B&W processing hasn't made all that much progress in the last 50 years, so his book is (IMHO) a very valuable and accessible resource. Although its main focus is B&W processing, it delivers the best explanation of color processes I have seen so far.
    • Anchell&Troop, The Film Developing Cookbook: a very short and concise resource, and the only book which looks at fairly modern recipes, including Crawley's formulas and necessary modifications to make a dev work well with T-Grain emulsions. Also the only book which describes Phenidone's properties compared to Metol.
    • Anchell, The Darkroom Cookbook: a much larger volume than the Film Developing Cookbook, mostly a big recipe collection.


    If you have a very tight budget, get at least the free book from Mees and Anchell&Troop's Film Developing Cookbook.
    Hi Rudeofus,

    I will download, but I will also take any advice you could give, since my the experience in photochemicals, today, is zero!

  2. #22
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    Quote Originally Posted by nworth View Post
    As stated above, sulfite has a complex functionality in developers, especially in metol based developers. In D-23 it acts as a silver solvent, preservative, and alkali to raise the pH to a point where metol will work. Just eliminating it will not work. Gainer did a number of experiments with eliminating sulfite from developers. They are almost all documented in the APUG archive. He used ascorbate as a combination developing agent and preservative (anti-oxident in this case). They all required a fairly strong alkali to make them work. Most of these developers were not terribly successful, although they were interesting.

    Sulfite-free developers from Patrick Gainer
    Original

    Sodium carbonate 1 tsp
    Ascorbic acid 1/2 tsp
    Metol 1/16 tsp
    WTM 1 qt

    2.5 ml of a phenidone solution (1/4 tsp (0.65 g) in 80 ml of denatured alcohol) may be substituted for the metol.
    Hello nworth,

    thanks for the clarification. Here, I'm going for maximum simplification, that's why I was thinking of subtracting SS.


    I will check out Gainer's work.

  3. #23

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    In a developer which uses ascorbate rather than sulfite it must be remembered the ascorbate also acts as a developing agent.

    Two other older but good books,

    L. F. A. Mason, Photographic Processing Chemistry
    Pierre Glafkides, Photographic Chemistry
    Last edited by Gerald C Koch; 10-09-2012 at 02:22 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  4. #24
    pierods's Avatar
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    Thanks Gerald,

    will check them out.

  5. #25
    Rudeofus's Avatar
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    Quote Originally Posted by pierods View Post
    I will download, but I will also take any advice you could give, since my the experience in photochemicals, today, is zero!
    You will see that you can pick up speed very quickly, as there are many helpful resources online.

    Just a short comment on Pat Gainer's work on ascorbate developers: see his articles here and here. One beautiful aspect of Ascorbic Acid is that it works both as a developing agent and as a preservative for Metol, that's why Pat was able to formulate sulfite free developers with acceptable shelf life. Unlike Sodium Sulfite, Ascorbic Acid is neither a silver solvent not an alkali, therefore Pat Gainer's recipes use TEA (Triethanolamine) as solvent and alkali.

    If all that doesn't make much sense to you right now, don't worry, after reading a few of the recommended books it will!


    PS: If maximum simplification is what you are looking for, use 2g NaOH with 2g Metol in one liter of water. If you can't get NaOH, use 10g/l Na2CO3. Expect some fog, some loss of film speed and poor grain, but you should get some results.
    Trying to be the best of whatever I am, even if what I am is no good.

  6. #26

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    Quote Originally Posted by Rudeofus View Post
    Don't forget that sulfuric acid is a weak acid (especially with regard to its second proton), therefore Sodium Sulfite is mildly alkaline.
    I believe you meant to say sulfurous acid and not sulfuric acid. Sodium sulfite is a salt of sulfurous acid (which IS a weak acid). Sulfuric acid is a strong acid and the corresponding sodium salt would be sodium sulfate.

  7. #27
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    Quote Originally Posted by pierods View Post
    Hi - I want to try because I like to experiment!

    Cool, so do I. I have around 140 chems in my formulary!! Enjoy it!..Cheers, Evan

  8. #28
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    Quote Originally Posted by Prof_Pixel View Post
    I believe you meant to say sulfurous acid and not sulfuric acid. Sodium sulfite is a salt of sulfurous acid (which IS a weak acid). Sulfuric acid is a strong acid and the corresponding sodium salt would be sodium sulfate.
    You are absolutely right and thanks for correcting me! Have mercy on me, English is not my native tongue
    Trying to be the best of whatever I am, even if what I am is no good.

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