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  1. #11
    Ian Grant's Avatar
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    Quote Originally Posted by Kirk Keyes View Post
    Part of the "magic" of staining developers when compared to chromogenic films is that the stain actually hardens the film adjacent to the area of development. This hardening is said to reduce the amount of growth/spread of the silver, making the image sharper.

    Chromogenic films just generate dye clouds, without the benefit of the hardening effect.

    I believe Sandy King posted info on resolution tests he had done with his developers here years ago.
    That's a good summary Kirk.

    Those effects are of course substantially greater with the older Pyro formulae in use from the late 1800's through to about WWII when their use had largely ceased.

    I've two interesting articles in BJP Almanacs on the use of modern Pyro developers, same autor but a few years apart. Ilford published a developer similar to Pyrocat HDbut using Pyrogallol in a Patent in fact it was a Phenidone variant of a Metol-Pyrogallol developer. The major difference is the dilution.

    Windisch's Fine grain compensation developer is a Pyrocatechin based staing developer with excellent resolution.

    Ian

  2. #12

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    But the effect Kirk refers to is the tanning I mentioned in the original post, which is separate from staining. So I assume, all other things equal (solvent effect etc), a formula producing a heavy stain is less "sharp".

    It would be interesting to make prints from the stained (imagewise) negatives after bleaching away all the silver. I wonder if the printed image would be sharp to the eye.

  3. #13
    Bob Carnie's Avatar
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    Or try making a print from the same series, one stained , one not.. I have done this and the non stained image if I remember correctly looked grainier and possibly sharper.

    I was convinced for a lot of Richard Avedon's work on grey background was unstained pyro development.

    btw I believe the tannin effect is probably the silver bullet of Pyro developers.

    QUOTE=Michael R 1974;1440106]But the effect Kirk refers to is the tanning I mentioned in the original post, which is separate from staining. So I assume, all other things equal (solvent effect etc), a formula producing a heavy stain is less "sharp".

    It would be interesting to make prints from the stained (imagewise) negatives after bleaching away all the silver. I wonder if the printed image would be sharp to the eye.[/QUOTE]

  4. #14

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    Quote Originally Posted by Ian Grant View Post
    That's a good summary Kirk.
    […]
    Ian
    From one survivor of the pyro wars to another, thanks!

  5. #15

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    Quote Originally Posted by Michael R 1974 View Post
    But the effect Kirk refers to is the tanning I mentioned in the original post, which is separate from staining. So I assume, all other things equal (solvent effect etc), a formula producing a heavy stain is less "sharp".

    It would be interesting to make prints from the stained (imagewise) negatives after bleaching away all the silver. I wonder if the printed image would be sharp to the eye.
    I'd say tanning and staining are the same thing, just different words used to decribe different effects of the pyro on the gelatin. Tanning refers to the physical hardening of the gelatin from the action of pyro developers, staining is the colored by-products generated from the action of pyro developers on the gelatin.

    I've bleached the silver out of pyro-developed negs to measure the stain density present without the silver present. (Actually, I've done it with Tmax 100 developed in XTOL, and it has a very faint stain present too, but it's very faint and probably not of any practical use.)

    I never tried printing these negs (I actually cut then up so I could scan them in a spectrophotometer...), but I seem to remember Patrick Gainer making prints from such negs.

    More stain makes more hardening, which I think would create sharper negs. But that's just a guess. Seems like something to test...
    Last edited by Kirk Keyes; 01-02-2013 at 10:25 PM. Click to view previous post history.

  6. #16

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    Kirk - are you sure you're right about this? My understanding is the stain has more to do with developer oxidation products (and it would seem the type of alkali plays a role here as well - influencing the stain colour to some extent).

    For example, if we add sulfite we reduce/eliminate imagewise stain, but is the gelatin hardening effect also reduced/eliminated?

    PS: I remember coming across some of those Pyro war threads not too long ago when I was searching for something (they were before my time). Wow did that ever get ugly!!

    Thanks
    Michael


    Quote Originally Posted by Kirk Keyes View Post

    More stain makes more hardening, which I think would create sharper negs. But that's just a guess. Seems like something to test...

  7. #17
    Philippe-Georges's Avatar
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    Quote Originally Posted by Michael R 1974 View Post
    But the effect Kirk refers to is the tanning I mentioned in the original post, which is separate from staining. So I assume, all other things equal (solvent effect etc), a formula producing a heavy stain is less "sharp".

    It would be interesting to make prints from the stained (imagewise) negatives after bleaching away all the silver. I wonder if the printed image would be sharp to the eye.
    - What is exactly the difference between TANNING and STAINING in Pyro development?
    Does the tanning results in staining or vice versa, or is staining completely different/independent from tanning, or is staining some kind of tanning or vice versa?

    - Right now I am scanning(*) the to me best negatives I made from 1992 till now, and the negs developed since 2006 in Pyro-HD (S. King) are showing better scanning results than the ones processed in 'normal' developers, or is it just 'me and the myth'?

    - I do prefer the tonalities and the grain of Tri-X in Pyro-HD, but this is strictely a personal 'esthetic' appreciation! AND this is the closeest I can get to Agfapan processed in Rodinal, perhaps these were mythic too?

    PS. I am not praising nor disapproving any kind of process, just wondering and seeking answers.

    (*) 6x6 and 6x17 negs wet scanned on a V750 + SilverFast 8.
    "...If you can not stand the rustle of the leafs, then do not go in to the woods..."
    (freely translated quote by Guido Gezelle)

    PS: English is only my third language, please do forgive me my sloppy grammar...

  8. #18

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    Quote Originally Posted by Philippe-Georges View Post
    - What is exactly the difference between TANNING and STAINING in Pyro development?
    Does the tanning results in staining or vice versa, or is staining completely different/independent from tanning, or is staining some kind of tanning or vice versa?

    - Right now I am scanning(*) the to me best negatives I made from 1992 till now, and the negs developed since 2006 in Pyro-HD (S. King) are showing better scanning results than the ones processed in 'normal' developers, or is it just 'me and the myth'?

    - I do prefer the tonalities and the grain of Tri-X in Pyro-HD, but this is strictely a personal 'esthetic' appreciation! AND this is the closeest I can get to Agfapan processed in Rodinal, perhaps these were mythic too?

    PS. I am not praising nor disapproving any kind of process, just wondering and seeking answers.

    (*) 6x6 and 6x17 negs wet scanned on a V750 + SilverFast 8.
    Tanning is the hardening of the gelatin which purportedly increases sharpness by limiting the "migration" and/or clumping of silver grains. The stain is produced by development by-products (under the right conditions). Imagewise stain (as opposed to general stain) adds printing density so that the total density is metallic silver + stain. If there is significant imagewise stain, less silver is required to form sufficient density and contrast - which may further increase sharpness slightly, and reduces graininess slightly. In addition, the stain (dye) fills in some of the space between the developed silver grains, which can further reduce graininess slightly. That is what this thread was about - ie does the "grain masking" effect of imagewise stain have an offsetting effect on sharpness.

    Hope this helps.

  9. #19
    Ian Grant's Avatar
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    There's two types of stain produced one just by oxidation and the other caused by the development process, these shouldn't be confused. The old myth of puting the fixwed film back in the spent developer just adds general oxidasion stain which you don't want as it can be patchy.

    The Tanning and staing in the development process takes place at the same time.

    Ian

  10. #20

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    IMO the perceived sharpness does not come from the acutance at the immediate edge of light/dark transitions but from adjacency effects ,often due to reduced agitation.I have attached scans of prints (high contast and dark to demonstrate the effect) from FX-2 (high perceived sharpness, large grain) and Pyrocat HD (lower perceived sharpness, small grain) form the same film.Sandy King, whose tests are probably more accurate than mine, did not find such a large difference in perceived sharpness between FX-2 and Pyrocat HD.
    Attached Thumbnails Attached Thumbnails FX-2 edge effect-1.jpg   Pyrocat HD edge effect.jpg  

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