Oops, I just woke up. I did hear of that problem when the now defunct
Archical Color Co. had its material manufactured by McGraw Colorgraph (now
defunct too) in Burbank. I think we now know which yellow pigment they were
using;-)
>Yes, I do remember the offending pigment. It was a Dalamar Yellow HSD,
>Type YW-911-P of Dupont. Back in the early 1980s, perhpas in late
It's an azo class pigment. I still have a jar around here somewhere. I
rejected it because it was not that permanent.
>1981, Richard Kauffman recommended a set of three-color pigments for
>carbro work, very similar to the set you mentions in your History and
>Practice of Carbon Processes. The yellow of the set was Dalamare powder,
>then Dupont's YT 858D. Kauffman told me that the liquid dispersion
>Dalamare had not worked for him, but the hassle of having to mix
>the powderded pigment made me try anyway. It worked perfectly, except
>when I tried to develop the yellow relief on the plastic it simply
>washed off. The liquid dispersion was Dupont's YW-911-P, a 53% solid
>dispersion in water/ethylene glycol containing nonionic/aniionic
>surfactant blends. Perhaps you or somebody else out there would
>recognize why a pigmented gelatin relief would not adhere to the
>plastic during warm water development.
pigmented gelatin does not adhere to anything easily if it is fully swollen
with water but I presume you would not have made that mistake with the
yellow layer only. It could be that a property of the pigment gave it a
teflon like quality on its outer surface, which would have been the
equivalent of overexposure.
Luis Nadeau
NADEAUL@NBNET.NB.CA
Fredericton, New Brunswick, Canada