From: Richard Sullivan FRPS (richsul@earthlink.net)
Date: 06/27/01-11:15:08 AM Z
While we are on this topic has anyone ever worked with hand coated
collodion POP. Stan Klimek said he saw a show in NYNY and there were
albumins, POP gelatins and POP "Collodions" and the collodions were
stunning and looked brand new. It could have been that they were processed
better. Colloidion POP sounds relatively easy to do and I have some (a)
formula here that I could post if anyone wants to try it.
--Dick
At 12:55 PM 6/27/2001 -0400, you wrote:
>Christine,
>
>Carl wrote:
> >If your negative is contrasty enough in the first place
> >(MUCH more contrasty than for silver or even Pt/Pd)
> >the self-masking of the silver POP process gives you
> >an elastic contrast. The more you expose, the lower
> >the contrast gets, because the highlights keep
> >gaining density while the shadows gain at a much
> >slower rate. So you almost can't have too much
> >contrast in the negative.
>
>I've been doing quite a bit of POP work over the last year or so. My
>experience is somewhat different than this. I have negatives that print
>beautifully in platinum and are a bit TOO contrasty for POP. I've observed
>that the self-masking effect only works to a point. If I try to decrease
>contrast by extending exposure time, often the shadows and lower-middle
>tones get too dark. The highlights do come in, but I end up with a print
>that is just too dark (but with nice highlights!). Based on step-wedge
>tests I've done, it's pretty clear that POP has a different contrast curve
>than my pt/pd papers. I haven't quantified it, simply an observation.
>
>I haven't printed with the sun in a long time, but my recollection is you
>get more contrast in open shade than in direct sun, but I may have that
>backwards. A little testing on your own will answer that question for you
>pretty definitively.
>
>One thing I did discover is that I can control contrast by the light
>source I use. I have both a mercury vapor NuArc plate burner and a
>40-watt UV tube box. Surprisingly, I get a considerably longer scale in
>the NuArc than in the UV box - i.e. the Nuarc is lower in contrast. What's
>cool about this is that I can get intermediate contrast levels by
>splitting the exposure between the two light sources. One of these days
>(yeah, right) I may do some step wedge testing to quantify what percentage
>of the exposure under each light source gives me what levels of contrast,
>but frankly, I'd much rather make prints.
>
>I've also found that negatives that are either just too flat or too thin
>to make an acceptable platinum print can make gorgeous POP prints.
>
>The only downside of POP for me is that some of those real beefy platinum
>negs can take up to 5 times the exposure compared to printing in platinum.
>An hour or more in the light box really slows down the work flow!
>
>FYI, the majority of my negatives are Ilford FP4 or HP5 processed in PMK
>or ABC+ (Rollo) Pyro.
>
>Of course, POP is just another niche market item, so I'm sure I can "kiss
>it goodbye" any day now... ; )
>
>Good luck! POP is a gorgeous material to print on, even if it's not
>hand-coated!
>
>Kerik
>www.Kerik.com
This archive was generated by hypermail 2b30 : 07/12/01-11:41:55 AM Z CST