Re: Gum Humidity Question
P.S. I will say, however, just as a general anecdotal observation,
that I haven't seen noticeable differences in contrast between prints
I've made at 100% humidity (in the air, not in the gum coating) and
those I've made at 60%.
Katharine
On Sep 26, 2006, at 2:31 PM, ericawd wrote:
According to Christina Z. Anderson and Kosar:
7. Humidity: The presence of a certain amount of moisture in a
coated and
dried layer is necessary for the hardening reaction. When dry, the
moisture
remaining varies with relative humidity. Completely dehydrated
or fully
swollen coatings do not show any light sensitivity at all, but in
between
the sensitivity is high when the humidity is high. Sensitivity
doubles with
increase of 30% humidity.
In my experience, I have found the above to be true. My question
is, in the experience of the gum printers, what effect might
humidity have on contrast? Lower humidity equals higher contrast
or vice versa? All other things being as equal as they can be with
gum.
Candace Spearman