Which chemical element affects the tone of the print?

Discussion in 'B&W: Film, Paper, Chemistry' started by smaidimaita, Oct 24, 2006.

  1. smaidimaita

    smaidimaita Member

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    Hello!
    Just built up my darkroom, just a few things missing, for example the paper developer.
    I have a couple of hundreds of Agfa MCP RC paper sheets, so I'll be using them for some time.
    If I understand, then it's harder to get cold tone for chloro-bromide papers.
    And I don't feel like making soft warm-tone pictures.
    So what interests me is -
    1) how to get my Agfa MCP RC cold tones.
    I think I could mix the developer myself, but the only supplier chemical substances has run out of hydroquinone, and there are not too many photoshops around here.
    and
    2) I've searched for the chemical ingredients for different paper developers, and what seemes strange to me is that there are 2 very similar developers, and the ratios of the chemical substances are very similar, but one of them is called a warm tone dev., but the other - cold tone.
    Here they are:
    the warm tone - (GAF-125)

    Water (125°F/52°C) 750 ml
    Metol 3 g
    Sodium Sulfite (anhy) 44 g
    Hydroquinone 12 g
    Sodium Carbonate (anhy) 65 g
    Potassium Bromide 2 g
    Cold water to make 1000 ml

    and the cold tone - Burki and Jenny
    Water (110°F/43°C) 750 ml
    Metol 3 g
    Sodium sulfite 40 g
    Hydroquinone 12 g
    Sodium carbonate (mono)* 75 g
    Potassium bromide 0.8 g
    Water to make 1000 ml
    Only the Potassium Bromide and Sodium Carbonate ratio changes noticeably.
    So which elements change the tonality?

    Thanks.
     
    Last edited by a moderator: Oct 24, 2006
  2. climbabout

    climbabout Member

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    Generally speaking metol is a soft working developing agent and hydroquinone is a more aggressive agent. The potassium bromide is the chemical that in increasing amounts will warm up the tone.
    Tim Jones
     
  3. Pragmatist

    Pragmatist Member

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    This is not true of brom or chlorobrom papers unless they are specifically a "warm" type. You may achieve a "cooler" tone by the use of a glycin based developer such as Ansco 130, or one of the Amidol preparations. Photographers Formulary sells both, as Formulary 130 & Formulary Amidol, Formulary Weston Amidol.

    You may wish to experiment somewhat with KRST (selenium toner) to achieve a richer black look. However on most papers that lean toward warm tones by design, selenium can add to that effect, moving toward a sepia depending upon time and dilution. If you really want cool/cold tones, consider using one of the developers listed above with Ilford Ilfobrom Galerie FB (deep, rich blacks), or Ilford Multigrade IV Cooltone RC (crisp, great tonality, very cool).
     
  4. Gerald Koch

    Gerald Koch Member

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    The easiest way to cool the tone of paper is to add benzotriazole to the developer. This was available as Ilford IBT Restrainer or Edwal Liquid Orthozite. The amount added controls the image tone. A 0.2% solution can be used. Start with 5 - 10 ml/l to start. Benzotriazole can be obtained from www.techcheminc.com.
     
  5. smaidimaita

    smaidimaita Member

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    Thanks. Got the idea.
     
  6. Tom Hoskinson

    Tom Hoskinson Member

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    Yes benzotriazole is the stuff to add for cold blue-black tones.

    For warm tones, Hydroquinone, Catechcol and Pyrogallol based paper developers are often used. P-Aminophenol developers like Rodinal also produce warm tones on paper.

    Here is a British Journal Warm Tone Paper Developer

    BJ Warm Tone Developer for Chloro-Bromide Papers
    Water-------------------------------------------570ml
    Potassium Metabisulfite-----------------1.3gm
    Soda Sulfite (Crystal)-----------------------28gm
    Potassium Bromide---------------------------4gm
    Pyrogallol-----------------------------------4gm
    Sodium Carbonate(Crystal)---------------28gm

    Published inThe British Journal Photographic Almanac, 1925, page 278

    Conversions from 1925 UK units to Metric were made with the digitaldutch WWW Converter and rounded up


    http://www.digitaldutch.com/unitconverter/
     
  7. Gerald Koch

    Gerald Koch Member

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    In the formula, I assume that crystal stands for decahydrate sodium carbonate and hexahydrate sodium sulfite. To convert the amounts to monohydrate sodium carbonate and anhydrous sodium sulfite you need to divide the amounts by 2.33 and 2.00 respectively.
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    In the argument of warmtone vs cold tone, the best solution is to use a warmtone paper in a warmtone developer and then back off to a cold tone developer or mixture of these to adjust the tone to your liking.

    Toning is often best done in the emulsion itself.

    PE
     
  9. Tom Hoskinson

    Tom Hoskinson Member

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    Thanks for the clarifications, Gerald.
     
  10. dancqu

    dancqu Member

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    I like that. The 1925 Almanac. They didn't by
    any chance suggest some papers which work
    well with that developer? Dan
     
  11. Pragmatist

    Pragmatist Member

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    Ones that bear distant relations to the ones made now...

    It was not that long ago that in any photo store there was a plethora of papers in all tones, finishes, and weights. And a number of brands as well, most of which are long gone, or represented discontinued lines. A recent casualty was Kodak Polymax Fine Art. That paper could be massaged from warm, to cold, to a superb neutral. GAHHHH...
     
  12. juan

    juan Subscriber

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    Actually, I rarely found lots of paper in photo stores - even when living in the relatively big city of Atlanta in the 70s. Lots of Kodabromide, a couple of other Kodak finishes, then there was usually only one other brand, either Ilford, Agfa, GAF or Luminos. I think I actually have access to more different papers now than ever.
     
  13. Tom Hoskinson

    Tom Hoskinson Member

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    Yes,

    "BJ Warm Tone Developer for Chloro-Bromide Papers"
     
  14. smaidimaita

    smaidimaita Member

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    How can I get a 0.2% benzotriazole solution if my benzotriazole is a powder?
     
  15. juan

    juan Subscriber

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    You can think of weight in grams and volume in ml to be equivalent. Thus for any volume of liquid, take .2% and use that amount in grams. For instance, if you need 100ml of solution, you add .2 grams of benzotriazole. Since that's probably hard to measure, add 2 grams to one liter.

    Now one of the real chemists will come along and tell how that's not quite right, but I've found it close enough for photography.
    juan
     
  16. smaidimaita

    smaidimaita Member

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    Okay, I've found some cheap benzotriazole and hydroquinone, but the bottle in which the benzotriazole crystals are kept doesn't seem to be very hermetically sealed. In one old book about the chemistries I found that benzotriazole can be even stored in paper packages. Is that true? Won't years in non-sealed glass botlle affect the blue-toning qualities of the benzotriazole?

    Guess it's not the same story for hydroquinone, which seems to oxidate in air very quickly?
    I didn't check the cover of the bottle for hydroquinone though.
    I live in Latvia, so in situation where the only hydroquinone supplier hasn't got any hydroquinone, it's pretty good to get any kind of hydroquinone at all, even if it's old.
    If I COULD get new, I wouldn't bother You with such questions.
    Thanks again.
     
    Last edited by a moderator: Oct 26, 2006
  17. Gerald Koch

    Gerald Koch Member

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    Benzotriazole is stable and you should have no problems with it, mine is 40 years old. Hydroquinone will slowly oxidize and should be kept in a glass bottle and away from heat and light. Unless it is very dark brown it should be good. What I have is quite old and has become a grayish color but still works.
     
  18. smaidimaita

    smaidimaita Member

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    Okay, thanks.
    Did some test prints, and with Burki and Jenny Cold-Tone developer there was no difference whether I add the benzotriazole or not (and no matter how much) - the Agfa MCP 312 RC still remained neutral tone, not a sign of the blue. That's a bit of dissapointment, though.
     
  19. gainer

    gainer Subscriber

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    Correct me if necessary, but is not the color of B&W paper decided more by grain size or distribution than by dyes? I think the action of BZT has nothing to do with any blue dye that it creates.
     
  20. Photo Engineer

    Photo Engineer Subscriber

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    Patrick, you are correct. No dye can affect the image tone of B&W papers in an imagewise fashion. Some paper supports are tinted a cream color or a warm browninsh tone for warm tones. Benzotriazole in the emulsion tends to darken tones towards purer blacks.

    Grain size and the form of the developed silver both affect the color of the final image.

    PE
     
  21. nworth

    nworth Subscriber

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    My experience is that paper tone is mostly set in manufacturing, but it can be influenced by the developer. You can usually get at least a warm neutral tone out of a warm tone paper by using a cold tone developer. If the paper is not really warm toned, you can probably get truly neutral tones, although some paper developer combinations have a bad way of going greenish black.

    As I recall, the conventional wisdom for cold tone developers is to use metol or amidol, make a fairly active developer (usually lower dilutions help here), and limit the amount of bromide to the least you can get away with (benzotriazole (BZT) both helps cool the tone an reduce the fog, so it helps here). There are a lot to choose from (you cited a pretty good one in the original post), and you can sort of look for things that follow the general rules. Things like Defender 54-D and 56-D work decently, and lower dilutions and BZT modificatios may help. There are also a number of Agfa (Ansco) and Kodak formulas that you can use as wellas a whole range of Amidol formulas.