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  1. #161
    Klainmeister's Avatar
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    With PMK I'd put the film developer back in for 2-3 minutes. I haven't done this since switching to Pyrocat, but I believe for PMK it's supposed to help stain and hardening....someone now correct me!
    K.S. Klain

  2. #162

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    Quote Originally Posted by jnanian View Post
    great thread !

    SNIP



    i have never heard of this ...
    how long do you put it back in the developer for ?

    i've never used pyro developers but use coffee developers
    which some people suggest is like its the 3rd cousin 4 times removed ..
    i might try this sometime ...
    The conventional wisdom was that with some Pyro formulations the stain can be intensified slightly in an alkaline after-bath. It didn't have to be the developer per se, just that the spent developer is a convenient alkaline solution that you'd have just used.

    However based on everything I've read, including Anchell/Troop, if anything happens at all in the after-bath, the increase is to the general stain, not imagewise stain. So it's basically just a higher base fog level. No value. We also have to remember a lot of these traditions came about when films were quite different. With current films some of them stain to different degrees etc. Not all Pyro formulas are the same either. Stain color, intensity etc depends as much on the other components of the developing solution (the alkali etc) as it does on the developing agent. One notable example is Wimberley's WD2D+. It has a carbonate alkali and produces a yellow-orange stain as opposed to the more typical yellow-green or green-brown, and Wimberley clearly states that with this developer the full extent of tanning/staining is achieved in development.

    Sandy King, Hutchings etc have all writen extensively on these developers, but in the end it is still somewhat murky and the only way to really know how a particular Pyro developer and film work together is to experiment, try a few things and see for yourself if stain intensifies in the wash, if an acid stop bath and/or fixer reduces stain, if a high level of sulfite after development (ie hypo clearing agent) reduces stain, etc etc.

  3. #163
    markbarendt's Avatar
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    Quote Originally Posted by Ian Grant View Post
    That's very true, but with staining developers curves don't tell us eveything, the colour of the stain has an effect at the printing stage and that varies between graded and variable contrast papers and also brand.

    Ian
    So, a color meter like a PML2 could read that right?
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  4. #164
    c6h6o3's Avatar
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    Quote Originally Posted by jnanian View Post
    great thread !

    SNIP



    i have never heard of this ...
    how long do you put it back in the developer for ?

    i've never used pyro developers but use coffee developers
    which some people suggest is like its the 3rd cousin 4 times removed ..
    i might try this sometime ...
    You don't. All this does is increase general stain, aka fog. Gordon Hutchings, PMK's inventor, has abandoned this practice. So should you.

    For really beautiful negatives to enlarge, try Ilford Pan F+ in PMK.
    Jim

  5. #165
    Ian Grant's Avatar
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    Quote Originally Posted by markbarendt View Post
    So, a color meter like a PML2 could read that right?
    I'm not familiar with a PML2 but you may need to read more than one colour channel, and its not staright forward.

    One reason this is a murkey area is the stain can act a a contrast filter, or even like a very mild safelight filter.

    When a negative is intensified in a Uranium intensifier it goes redder and is visually less dense but prints with significantly more contrast and as far as a blue sensitive papers concerned needs more exposure.

    Some staining developers give a yellowish stain others redish and this can vary depending on the film as well.

    I use staining developers for prints occasionally and once the stain is formed the choice of stop bath and fixer has no effect on the stain.

    The staining is the same after an alkali fixer or conventional Rapid fixer (unhardened) and is not affected by HCA (sodium sulphite) either.

    Ian

  6. #166

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    thanks for the info and reasons behind the after-bath...
    my coffee stained negatives are stained and fogged enough
    as they are ... so i think i will avoid the after-bath

    interesting just the same ...

    thanks !
    john
    silver magnets, trickle tanks sold
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  7. #167
    markbarendt's Avatar
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    I can definitely see where measuring contrast could be problematic.

    Quote Originally Posted by Ian Grant View Post
    I'm not familiar with a PML2 but you may need to read more than one colour channel, and its not staright forward.

    One reason this is a murkey area is the stain can act a a contrast filter, or even like a very mild safelight filter.

    When a negative is intensified in a Uranium intensifier it goes redder and is visually less dense but prints with significantly more contrast and as far as a blue sensitive papers concerned needs more exposure.

    Some staining developers give a yellowish stain others redish and this can vary depending on the film as well.

    I use staining developers for prints occasionally and once the stain is formed the choice of stop bath and fixer has no effect on the stain.

    The staining is the same after an alkali fixer or conventional Rapid fixer (unhardened) and is not affected by HCA (sodium sulphite) either.

    Ian
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  8. #168

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    Quote Originally Posted by markbarendt View Post
    So, a color meter like a PML2 could read that right?
    It certainly can. Use the magenta/green and yellow/blue channel.

    The other problem with trying to make predictions based in densitometer readings is that not only does the stain have differing absorbance in blue and green, but VC papers have varying sensitivities in to blue and green light.

    Many years ago, I did some looking into the stain and I took some film developed in PMK and PyroCat HD and I bleached out the silver and then measured the absorbance of these films with a scanning spectrophotmeter. Here's a pdf I made that shows the difference between the stain of these two developers.

    http://www.keyesphoto.com/Resource/T...rocat_scan.pdf

    It believe this data that PyroCat HD gives more UV absorbance/density than PMK, which is useful with alt processes. And is shows that PMK is going to have a greater compensating effect with PC papers than PyroCat HD.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  9. #169

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    This is consistent with what I've seen, and Sandy King's tests/writings. It makes sense. His Catechol developer stains brownish while most Pyro developers range from brown-green to green-yellow, yellow and even yellow-orange. There is more compensation on VC papers with green/yellow stain.

  10. #170
    destroya's Avatar
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    great thread. and very informative for someone like me who knew nothing about pyro developers.



 

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