Re: humidity and gum coating
On Sep 2, 2006, at 3:53 PM, Tom Sobota wrote:
"The paper will be more easily coated if it is immersed in water
and blotted before being placed on the board."
Neblette, "Photography,its principles and practice", London 1927
Surely, people have tried this before.
Thanks for the citation. I would have thought people had tried it,
but it's not something I'd ever seen recommended, so I was curious
about others' experiences, even though I had tried it myself and
found it worked well enough.
Me too. Madrid, where I live, is very dry, so I have tried all kind
of tricks to make coating easier. Wetting the paper works with some
papers but with others you get irregular spots. What I do now is
simply to add water in the mixture.
I can believe it about different papers behaving differently; I'll
try it with my current favorite, Arches bright white, and see how
that works. Unfortunately I didn't note what paper I used for that
earlier experiment, but I would guess that was from the days I was
printing on Arches Aquarelle.
I didn't want to add liquid because I don't like to dilute either the
pigment or the dichromate, but you probably wouldn't have to add a
whole lot of water to get the coating to smooth out. How much do you
add? At any rate, we're back up to 65% here today, even though it
still feels fairly dry, and the one print I've done so far today,
the coating went on like a charm, so it looks like my immediate
emergency is over.
Katharine Thayer wrote:
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
At any rate, that combined with your explorations around
palladium have led me to musing about whether humidifying might
give a better result.
On Sep 1, 2006, at 10:10 PM, Christina Z. Anderson wrote:
Happy Labor Day weekend everyone! It may be a true "labor"
weekend for this
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
came in and I was ever so excited to see if the new batch would
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 on Cot
320 this summer: humidify 30 minutes before coating and 30
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 and not
before coating, humidifying both before and after. I built myself a
makeshift humidity box with a couple of trays and stuck a gauge
(Of course in the meantime throughout these tests I am racing
first to the
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,
important than Everclear or having the paper humidified before.
humidified before coating, the paper tone was greyer and duller.
humidified after coating, for 30 minutes (70% humidity) while the
drying, there was no bleeding. So it must be as Clay suggested--
the stuff is
drying too quickly on the paper surface and not sinking in
enough. It was
so bad on a couple of my test sheets tonight that I could
literally take my
finger, wipe the wet surface of the print, and have black stains
fingertip. I was losing quite a bit of density in the print all
including highlights, and even had serious staining/bleeding into
highlight area, too.
So tomorrow I am going to have to develop a new set of curves
after-coating humidity factor, and will continue this procedure
to see if,
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
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.