humidity and gum coating (was: Re: palladium bleeding once again
Chris, this makes me wonder if anyone has ever tried humidifying
paper for gum coating, to make the coating easier in dry climates.
The reason I'm wondering this is that my humidity, ordinarily >90%,
has been way down for the last couple of days (17% yesterday
afternoon) and I was having a heck of a time getting a smooth coat
with my usual straight gum (no added water) mix. I decided that if
this keeps up (unlikely) I'll need to start adding water to the mix,
but your troubles with palladium gave me to wonder if anyone has
reported humidifying the paper to make the coating easier. I do know
that I once coated and printed on wet paper, just to see if it could
be done, and it coated beautifully and printed fairly well, except
for a sort of mottled effect in the background. Here's the test
print I posted at the time:
At any rate, that combined with your explorations around palladium
have led me to musing about whether humidifying might give a better
On Sep 1, 2006, at 10:10 PM, Christina Z. Anderson wrote:
Happy Labor Day weekend everyone! It may be a true "labor" weekend
household after all, because my daughter is having her baby in my
any day (or hour) now. Hmmm...that sounds strange....we do have
in MT....ohhhh, never mind...
At least I got somewhere today with the bleeding issue. My Platine
came in and I was ever so excited to see if the new batch would be
and not bleed. Alas...it still bled like crazy.
SO, it helped that Mark Nelson said that at the Formulary (also in
MT--similar humidity) they had to do two things to get good prints
320 this summer: humidify 30 minutes before coating and 30 minutes
I've watched the humidity all summer and it has hovered around 30%.
I messed around with the humidity and Everclear variables--using
or not, humidifying before and not after coating, humidifying after
before coating, humidifying both before and after. I built myself a
makeshift humidity box with a couple of trays and stuck a gauge in
(Of course in the meantime throughout these tests I am racing first
hardware store for screening and then to the liquor store for my
Everclear...I thought of downing the bottle on my way home.)
What I found was it was most important to humidify after coating, more
important than Everclear or having the paper humidified before. If I
humidified before coating, the paper tone was greyer and duller. If I
humidified after coating, for 30 minutes (70% humidity) while the
drying, there was no bleeding. So it must be as Clay suggested--the
drying too quickly on the paper surface and not sinking in enough.
so bad on a couple of my test sheets tonight that I could literally
finger, wipe the wet surface of the print, and have black stains on my
fingertip. I was losing quite a bit of density in the print all over,
including highlights, and even had serious staining/bleeding into the
highlight area, too.
So tomorrow I am going to have to develop a new set of curves with
after-coating humidity factor, and will continue this procedure to
in fact, the bleeding completely stops. I just have to find
build me a drying/humidity rack, now....
I'm still puzzled, though, why during the last couple years I never
experienced this, and now I do. If someone has a friend at Arches,
you ask if their paper sizing has changed in the last year?
BTW, that green ink on the Epson 2400 is sure as heck dense.