Re: Contrast in gum bichromate

Judy Seigel (jseigel@panix.com)
Wed, 14 Jun 1995 14:49:12 -0400 (EDT)

On Wed, 14 Jun 1995, Virginia Boehm wrote:

> > Another key factor is the gum to pigment ratio! I got tired of soft
> looking prints and doubled the amount of pigment I was using. I now
> have colors on my newer stuff that are brighter (and consequently in
> comparison with one another, have more contrast, than anything I've
> seen on tri-color gum before.
>
> I suspect this would have an impact on monocolor gum as well. The
> pigment is suspended in the gum, not disolved in it. Look through a
> magnifying glass at a gum print and you can see the dots of pigment
> clearly. More pigment, and the dots are closer together and hence the
> print appears more contrasy. A point would come, however, when more
> pigment would become counterproductive since it would serve to "dilute"
> the gum.

You're right Gini. Probably the reason I didn't think to mention amount
of pigment was because
my personal struggle is usually in the opposite direction -- a
tendency (no doubt caught from my students) to pile on so much pigment
that the print loses translucency and delicacy. Also, too much pigment
can be a source of flaking (because it has its own gum content) and
staining (the gum will suspend just so much pigment) if
those bother you. (I hate it when somebody's nose flakes off!)

I suspect, too that you can get away with denser pigment in tri-color,
where the coats aren't exact duplicates, than with monochrome, where
the next coat and all other nexts are likely to go right in the same
places. Anyway, you do make tri-color sound inviting ......

Cheers,

Judy