Mold, was Re: Dark reaction of gum coating
I had a similar experience many years ago. My wife and I did a two
month trip in the summer (June through early August) to Spain and
France, and before leaving we closed down the house. When we returned
in August there was mold everywhere -- on the walls, behind the
walls, on the furniture, etc.etc. We arrived back home about 5 am
after some 34 hours in transit and conditions forced us to
immediately start cleaning away mold. Very unhappy experience.
Now when we leave home the air conditioning stays upstairs and
downstairs. I raise the temperature a bit over what we consider
normal but the small price to pay is well worth it to me to avoid
At 3:05 PM -0600 8/2/07, Christina Z. Anderson wrote:
I'd say it's neither factor alone as much as together. My feeling,
BTW, is that putting a coated print in a black envelope with a
weight on top (no air) extends the safe period, tho I never tested
Heheheh, I should have clarified something that Don and I have in common:
When I lived in South Carolina, just a couple hours from Don, and
was rabidly gum printing for 2 years, it was the first time I ever
lived in a house with air conditioning. One time Tom and I decided
to just shut it off, thinking, so what if the house gets hot when
we're not there. WELL, we didn't realize that HUMIDITY does the
real damage. You can mold your walls and camera gear if the air
conditioning is not used. In fact, while I was in grad school
somehow the air conditioning was turned off in our gang grad student
huge darkroom area and we came back in August to the darkroom
completely molded, ceiling, walls, lenses, even the TIMER on the
enlarger (metal) was covered in mold!! I was so blown away by this.
The university had to come in and do one of those hepa-clean
processes. We lost a bunch of stuff.
My suggestion for the black bag outside in the garage was merely to
have the coated paper in high humidity and high heat (presuming
plastic isn't able to hold out all moisture--no weight used, not air
tight). If left in the sun, there would also be the heat factor in
spades--one semester I left all sorts of plastic bags, black and
seethru, taped to my outside south facing wall to test some factors
with gum. I have never experienced humidity like I did in the South.
According to Kosar, if one of the factors (heat, humidity, time, air
flow as Judy suggests, and as Katharine says dichromate
concentration) is high that will increase DR.
In practice, I used to coat 6-9 large gum prints in my air
conditioned house down there that was if I remember correctly
somewhere between 35 lowest and 55% highest humidity, and that could
mean wait times for the final print to hit the water to be as long
as two hours if I moved right along. In room light. All prints
worked fine, tho perhaps in practice I left the last one to develop
longer. So my rule of thumb in South Carolina was that I did not
expect the paper to last til the next day, but in MT it is not a
concern I think about. I do use 15% dichromate, though (half
strength am di) and down in SC I used 1/4 strength for a time til I
got lazy measuring it out, and that could certainly account for some
difs we all observe.
When I read that Livick and Arnow do not print in the summer months
I was pretty surprised, but I bet it's that they had such a
predictable workflow that when humidity came, they didn't think to
adjust practice to suit it. If my summers were verboten for gum
printing I'd be in deep trouble.
Now ask me how living in MT wreaks havoc with my palladium printing
with such low humidity....