Re: Help with gum printing: was: Transparency

Katharine Thayer wrote:
>
 in
> gum printing, transparent pigments remain transparent throughout their
> range of printing concentration, meaning that they disappear against a
> dark background. They blend with the colors underneath, but they aren't
> visible above them, whereas more opaque pigments are visible over a
> black background

This of course is why many people stick to the "rule" to always print
yellow first in tricolor, because there are few yellows that are
completely transparent, and a semi-transparent or semi-opaque yellow
will insinuate itself as a veil of yellow rather than blending with the
other colors to make a mixed black as a transparent yellow will.

You're right that there are few pigments that are opaque enough in
themselves to completely cover black; this is especially true in
transparent watercolor formulations, which is why gouache, which is
especially formulated for opacity, is a better choice when one wants to
print a visible light image over a dark background.
Katharine
Received on Wed Jan 19 14:18:43 2005