> It may have something to do with the characteristics
>of the gelatin being used for printing that necessitates
>"clearing" for some using plexiglas to develop carbon
>transfer images and not for others.
> I for one always find it necessary to use a clearing
>bath for monochrome carbon . If one carefully inspects
>a cleared print on plexi next to an uncleared one
>( while dry ) against a white background one may see
>that there is indeed a need to clear. Otherwise ,
>please let me know the source of your gelatin supplier
>so that I can eliminate this step.
Phillip,
It would be interesting to see the results of actual tests. It may, as you
suggest, have something to do with the characteristics of the gelatin: it
may also simply be a question of how long the image on plexi or polyvinyl
is left to wash.
As for gelatin sources, I have used, among others, the following gelating:
Knox; a 175 Bloom gelatin from US BioChemical Corporation; a 100 Bloom
gelatin from Formulary; and a 250 Bloom gelatin from US BioChemical
Corporation. I have strong reason to believe that these were all porcine
skin gelatins, and I never had any reason to clear after washing when using
polyvinyls supports.
Sandy King