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  1. #41

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    Quote Originally Posted by Peter De Smidt View Post
    The stain has more effect on the higher negative densities. So at about .1 above film base plus fog, i.e. really low film density, there isn't much stain. Up around 1.3 above fb+f there will be much more stain, with stain making up about 40% of the total density. Hence, on the stain has more effect on higher negative densities, which equate to brighter sections of the print. With PMK the stain tends to be very green. Since green light means low contrast on VC papers, this means that a PMK negative tends to have less contrast in the highlights than in the mid or lower print tones. This can be a good thing or a bad thing.
    Dear Peter,

    Thanks for the clarification from greater experience/knowledge. I've only ever seen yellowish (including yellowish-brown, yellowish green) but I understand you are right.

    Do I understand correctly that some staining devs do in fact provide fog-level stain at printing densities, or am I misreading the literature?

    Cheers,

    Roger
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  2. #42

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    Quote Originally Posted by Roger Hicks View Post
    Dear Peter,

    Thanks for the clarification from greater experience/knowledge. I've only ever seen yellowish (including yellowish-brown, yellowish green) but I understand you are right.

    Do I understand correctly that some staining devs do in fact provide fog-level stain at printing densities, or am I misreading the literature?

    Cheers,

    Roger
    Roger,

    As was mentioned earlier, the actual color of the stain varies a great deal depending on developer, film and pH. It can be orange, yellow, brown, green, or even black.

    Second, modern pyro formulas do not produce much B+F stain when used as indicated. When used for long develoment times to bump contrast some formulas produce much lower B+F than other.

    Finally, the stain is proportional, which means that it is greatest in the upper mid-tones and highlights, where it has more impact on printing than silver density. Since grain is always greatest in these tonal values, grain masking is much greater with higher contrast negatives than with low contrast ones.

    Pyro staining developers are not magic bullets, but they are as close to real silver bullets as you can come.

    Sandy King

  3. #43

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    Quote Originally Posted by sanking View Post
    Roger,

    As was mentioned earlier, the actual color of the stain varies a great deal depending on developer, film and pH. It can be orange, yellow, brown, green, or even black.

    Second, modern pyro formulas do not produce much B+F stain when used as indicated. When used for long develoment times to bump contrast some formulas produce much lower B+F than other.

    Finally, the stain is proportional, which means that it is greatest in the upper mid-tones and highlights, where it has more impact on printing than silver density. Since grain is always greatest in these tonal values, grain masking is much greater with higher contrast negatives than with low contrast ones.

    Pyro staining developers are not magic bullets, but they are as close to real silver bullets as you can come.

    Sandy King
    Dear Sandy,

    My understanding of 'proportional' has always been that it means 'proportional to the density of the silver image'. If it is more or less effective at one end of the curve than the other, then surely it is super-proportional or sub-proportional?

    Nor am I entirely clear on the concept of 'black' stain. I have never seen an absolutely neutral stain (and very few neutral dyes). From friends at Kodak I understand that a black E6 dye is something of a Holy Grail.

    You know far more about this than I, but I am eager to learn.

    Cheers,

    Roger
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  4. #44

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    Amidol can produce a black stain, proportional to exposure.

    Quote Originally Posted by Roger Hicks View Post
    Dear Sandy,

    My understanding of 'proportional' has always been that it means 'proportional to the density of the silver image'. If it is more or less effective at one end of the curve than the other, then surely it is super-proportional or sub-proportional?

    Nor am I entirely clear on the concept of 'black' stain. I have never seen an absolutely neutral stain (and very few neutral dyes). From friends at Kodak I understand that a black E6 dye is something of a Holy Grail.

    You know far more about this than I, but I am eager to learn.

    Cheers,

    Roger
    Roger, when used in a film developer recipe, Amidol can produce a black colored image stain that is proportional in density to the amount of exposure.

    The amount, density and color of image stain can be difficult to evaluate visually. I use densitometry and make prints (mostly LF contact prints). The stain's ability to block light is the important feature, of course.
    Tom Hoskinson
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  5. #45

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    Quote Originally Posted by Roger Hicks View Post
    Dear Sandy,

    My understanding of 'proportional' has always been that it means 'proportional to the density of the silver image'. If it is more or less effective at one end of the curve than the other, then surely it is super-proportional or sub-proportional?

    Nor am I entirely clear on the concept of 'black' stain. I have never seen an absolutely neutral stain (and very few neutral dyes). From friends at Kodak I understand that a black E6 dye is something of a Holy Grail.

    You know far more about this than I, but I am eager to learn.

    Cheers,

    Roger
    Roger,

    Stain is proportional to silver density. As silver density increases, stain density increases proportionally. Proportional increase means "at a constant ratio or relation", not in an equal amount.

    As for color, I have not said that there is an absolute black stain, only that the color of stain varies a lot and some stains are visually black. That they are absolutely black is not a point I was trying to make.

    Sandy

  6. #46

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    Quote Originally Posted by sanking View Post
    Roger,

    Stain is proportional to silver density. As silver density increases, stain density increases proportionally. Proportional increase means "at a constant ratio or relation", not in an equal amount.

    As for color, I have not said that there is an absolute black stain, only that the color of stain varies a lot and some stains are visually black. That they are absolutely black is not a point I was trying to make.

    Sandy
    Dear Sandy,

    Sorry, too late at night, and I'd been out shooting all afternoon (Efke IR). I see what you mean. Yes, the effect is greater in the highlights, because the silver image is more dense -- but I had not thought that this was disputed.

    As for the black stain, I was interested in what colour it was when 'diluted', as it were. Not that it matters much.

    As I say, you have more experience of this than I, and I am eager to learn.

    Cheers,

    Roger
    Free Photography Information on My Website
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  7. #47
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    Haris, if you are using Efke films, another reason to use a pyro or catechol developer is that it will harden the soft Efke emulsion and make the film less prone to scratching.

    And here is an article on amidol as a negative developer.
    juan

  8. #48

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    Quote Originally Posted by juan View Post
    Haris, if you are using Efke films, another reason to use a pyro or catechol developer is that it will harden the soft Efke emulsion and make the film less prone to scratching.

    And here is an article on amidol as a negative developer.
    juan
    Interesting article and recipe Juan. As the article mentions, this is not a staining amidol developer. However, If you reduce the amount of sodium sulfite in the recipe, it will produce proportional image stain.
    Tom Hoskinson
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  9. #49
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    I will only use staining developers (pyro) and after much much experimentation have settled on TMax with Pyrocat-HD. Once you print pyro negatives, it is hard to ever go back.

    Gordon Hutchings 'The Book of Pyro' is filled with lots of background reading on just what happens with staining developers.

  10. #50

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    Thank you juan.
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