Search results for query: sulfite solvent

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  1. Photo Engineer

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    PC-TEA + Sulfite

    To get a suitable solvent action from sulfite, you will probably need about 25 grams / liter minimum in the working solution. Below that level, the solvent action of sulfite falls off rapidly. PE
  2. Photo Engineer

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    Why so much Sulfite?

    Sulfite is a preservative and mild solvent which gives better image quality. PE
  3. Photo Engineer

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    Sodium sulfate/bisulfate interchangeable?

    You are confusing solvent with restrainer. A solvent dissolves grain and is used in Microdol and D-76 (Sodium Chloride and Sodium Sulfite respectively). A restrainer slows down development, lowers fog, lowers contrast and decreases speed. It is usually used to restrain fog. PE
  4. Photo Engineer

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    RA4 Paper Negs Colour balance help?

    HC110 is a high solvent developer, and papers are mainly AgCl (Silver Chloride). They dissolve easily in high solvent developers and you lose detail in the top (cyan) layer and can also lose speed. I use Sulfite in the CD to reduce contrast. PE
  5. Photo Engineer

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    Replenished developing systems

    Well, that is using the sulfite at high levels for the same reason as in other formulas. I was thinking of low sulfite developers which could be speeded up a tad with no significant sulfite (solvent) effect. Also, "H" acid and "J" acid are often used in these formulas as "colorless" couplers...
  6. Photo Engineer

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    New HC-110 Formula

    I would even worry about HCl. Chloride ion can be a solvent, and in the wrong concentration it could hurt the balance of desired solvent effect from Sulfite. PE
  7. Photo Engineer

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    Progress on XTOL-concentrate

    Mark; Temperature has a profound effect on crystallization with the rate generally going up as temperature goes down. TEA, AFAIK, is much less of a silver halide solvent than Sulfite. PE
  8. Photo Engineer

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    Rodinal Substitutes?

    Patrick, simply put, chloride is both an antifoggant and a silver halide solvent. Balance between those two properties and the property of being a silver halide solvent along with sulfite being a silver halide solvent is criticial. I am a chemist and this boggles me. It should give you...
  9. Photo Engineer

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    Improved version of DS-10 by Ryuji Suzuki?

    Mark; Great experiments. Before you know it, someone else will be selling this stuff! You are looking at the solvent activity of Sulfite at higher concentrations and also the buffer capability (to a lesser extent). There you are. Sulfite is also your preservative to a certain extent...
  10. Photo Engineer

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    Monobath Developers

    Yes. The sulfite is a strong solvent and can wipe out AgCl images in the right emulsion. It does not work with all of them, but does a real job on others. PE
  11. Photo Engineer

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    Reversal RA, not entirely successful

    Dektol at 1:3 has a rather low level of sulfite. You have to have a very active developer for the first developer and low solvent to get the right dmin and dmax. PE
  12. Photo Engineer

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    Strange effect of Ascorbic Acid + DEA

    DEA and TEA, being organic bases and SO2 being an inorganic acid, they react rather strongly to form the salts of the respective bases and acids. In the absence of water, one calls them adducts because they are held together by electron bonding. In water, they disassociate, but do not form...
  13. Photo Engineer

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    Improved version of DS-10 by Ryuji Suzuki?

    Ok, Sulfite is a silver halide solvent. Long contact with concentrated Sulfite allows many many things to happen. The simplest way to explain this is that the tiny slow grains or the low iodide slow grains will dissolve courtesy of high Sulfite. The longer you are in contact with this...
  14. Photo Engineer

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    "Special" Developers for High Iodine Emulsions

    Silver halide solvents include Hypo, Thiocyanate, Sodium Sulfite, and Sodium Chloride in decreasing order of activity. So, where 1 g/l of hypo will be a good solvent, you may need 100 g/l of sodium chloride. PE
  15. Photo Engineer

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    Improved version of DS-10 by Ryuji Suzuki?

    Sulfite at this level tends to act as a mile silver halide solvent much as it does in D-76. As we all know, it is also a stabilizer (antioxidant) and a mild alkali or a weak base. PE
  16. Photo Engineer

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    Adding Ammonium Chloride to developer -- who has tried it?

    I'm confused. You mention Ammonium Chloride and Sodium Sulfite. Yes, the sulfte does as you say, but Ammonium Chloride is a very powerful silver halide solvent, much more so than sodium sulfite and also can cause fog. It is very critical that you get the right concentration for the film in...
  17. Photo Engineer

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    Strange effect of Ascorbic Acid + DEA

    Well, 2 bath developers are tricky because they rely on imbibition of part A which depends on swell and original emulsion thickness, hardness and other characteristics such as pH. So, the activity of 2 bath developers is very hard to judge or predict when formulating one. It will also tend to...
  18. Photo Engineer

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    Defective Acros or bad rodinal?

    Borax will lower pH and Sulfite will increase silver halide solvent action as in D76. Neither would be very good for Rodinal. However, if you are having problems with common developers with common films, then the film is defective or the process is faulty. PE
  19. Photo Engineer

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    Sulfite-free fixer

    Two part sulfite free developers, no matter what the solvent, once mixed for use will only last for an hour or so. So, your statement only applies to two part developers or single part concentrates with no water present. That should be made clear. PE
  20. Photo Engineer

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    Kodak Supra Endura F

    I would not suggest a high solvent or high sulfite film developer as the first developer. It usually leads to excessively high contrast and large speed losses. The chloride emulsions in Endura paper are very sensitive to these types of developer. I use Dektol 1:3 for 1 - 2 mins at 68...
  21. Photo Engineer

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    Excess sulfite in print developer - effect?

    Sulfite is a Silver Halide solvent. Depending on the Chloride content of your paper, it will have a varying effect. On a pure Chloride emulsion you can lose lots of speed and gain contrast, but on a high Bromide paper there may be little or no effect. PE
  22. Photo Engineer

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    Sulfite quantum--Tmax 100 developer--single bath--metol

    Well, low agitation tends to enhance edge effects. Is that what you want? Also, to avoid the solvent effects of sulfite, 10g/l or less is desired. And, desiging a film developer that gives an image may be easy, but designing one that gives 'the' image is hard. PE
  23. Photo Engineer

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    "High sulfite concentrations" and t-grain films.

    That depends. Sulfite is a poor silver halide solvent actually. You can use D76 as a monobath for Chloride emulsions and Chlorobromides with great speed loss, but it does not happen with bromoiodides. A high iodide t-grain or a t-grain with epitaxy could hardly be touched by the sulfite at...
  24. Photo Engineer

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    does pH affect grain and film speed?

    I think my comment was oversimplified. In this type of experiment, where you are using Sulfite, Bisulfite or Metabisulfite to attain varying pH values, the amount of solvent will vary and thus the effects on image structure will vary. If you want to experiment, you should select one level of...
  25. Photo Engineer

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    sodium sulfite in developers

    Sulfite becoming Sulfate no longer offers solvent action (D-76 for example) and no longer offers oxidation protection (almost all developers). Thus, images in D-76 are degraded and all developers go bad faster. This is why I am not an enthusiast for the average person mixing their own...
  26. Photo Engineer

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    Commercial Devs. vs. Custom Chemistry

    Dan, you are absolutely right. Where was my mind. I was thinking sulfate and sulfite, when writing about bi-sulfate and bi-sulfite. AAAGH. So sorry all. Both the bisulfite and bisulfate are acids, the sulfite is slightly alkaline and the sulfate is neutral. None of the four can be...
  27. Photo Engineer

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    Mixing your own E6 / C41 chemistry?

    Well, the E6 CD usually contains a powerful organic silver halide solvent such as Ethylene Diamine Sulfate. In addition, a stop between the CD and the Ferri Bleach should contain some Sodium Sulfite. And, the Borohydride reversal bath is not good for stability IMHO. It looks so far like two...
  28. Photo Engineer

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    New Products

    Ian; Your key word here is a post fix for archival purposes. The OP on this topic asked to avoid that! That is what stopped me! Peter; Solvent developers (non H2O) use sulfur dioxide gas in TEA or the like to avoid insoluable sulfite salts. The same can be said for halide salts...
  29. Photo Engineer

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    Purity of raw chemicals

    In going over all of my years of experience, I have found virtually no cases of an "impurity" causing a given reaction in any sort of chemical reaction. In fact, the opposite is true. Impurities in most all cases tend to inhibit the desired reactions. Cases in point include halide salts...
  30. Photo Engineer

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    film categories: which are "retro" and which are not?

    If this were true, then D76 would be less than optimum with modern films. But, this is not true. D76 is just as fine today as it was then. PE
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