RE: To Don (and others, was: )RE: Gum questions - 101

Hi Cor,

>
Hi don (and others),

I already considered myself a very modest gum printer: I sensitze only1
sheet (4*5 or 8*10) at a time, and you do 6-8 sheets a time (so making my
gum printing efforts almost minute..;-)..), so I wonder: do you see
differences between these sheets? I understood that the drying time of a gum
sheet is also a variable, and there must be a considerable difference
between these sheets before you can expose them. Or do you use more UV
printers or you work with differnt negatives at the same time, or..

>

I read your e-mail early this morning and I've not had a chance to respond
until this evening. Since then Chris Anderson has replied with a much more
experienced voice than myself. But here is my answer:

I coat this many sheets because the gum mixture that I mix can coat that
many sheets. I will however cut this quantity in half if I wish to do a
shorter printing session. Thus far my gums have all been made using digital
negatives printed with an Epson 2200, all are CMY seperations (except for
two images which were output as CMYK seperations.)

I work with 2 to 4 images (negatives) at a time and like Chris I start out
with a first layer (or exposure) of traditional cyanotype (although I have
used prussian blue once with poor results.) My basic exposure for the
cyanotype exposure is 6 minutes but preliminary testing with Mark Nelson's
PDN system indicates that the exposure time should be longer (that would be
the uncurved DMAX time.) Working with the curve I have though 6 minutes
seems to work okay - but not purr - feectly. The Yellow and Magenta layer
receive a 4.5 and 4.75 minute exposure respectively.

With this work flow I don't seem to suffer any problems due to the dark
effect. Livick on his web site suggests that a 30 min drying time should be
used and no more to avoid degradation of the sensitized gum coat. It is
without a doubt in my mind that Livick knows what is doing and I'm not going
to dispute anything he suggests. However I can say like Chris did that the
main effect I have observed is that the automatic development time does get
longer. Normally I develop for 20 minutes but I usually peek at the print
after 5 minutes and then 10 minutes just to confirm that things are really
working. My water temp is about 75F. To accommodate all of these prints I
have six trays which I use to develop prints. So once I start exposing the
my activity in the darkroom becomes quite busy. I let my coated prints dry
for about 20 minutes with the aid of a fan that blows up into my drying
racks. After the first print has dried 20 minutes I find it is dry and safe
to start the printing cycle.

After reading as much as I can about gum printing (online and from a few
printed sources) and getting a huge amount of information from Chris it has
become apparent to me that gum printing no matter how hard you try isn't a
precise photographic process. For me the key to success is simply to be
methodical, learn from your mistakes, and don't be afraid to stand on the
shoulders of other gum printers on this list; who all have contributed to my
understanding of gum printing. Just pick a name from those that have posted
here and I've benefited in one way or another, directly or indirectly, from
their advice.

I think Sam Wang's concluding paragraph from his article, 'Tri-Color Gum
with Cyanotype' found on the Unblinking Eye web site, summarizes the
unvarnished truth about gum printing :

"There is just no one-size-fits-all way to make gum prints. I believe that
the variables are too numerous for anyone to lay out a failsafe method. In
fact, I'm convinced that I have just scratched the surface in terms of the
potentials of this medium. Not infrequently as I go through my reject piles
wondering which ones I ought to discard, the prints I rejected earlier
because of some perceived technical flaws may present themselves on second
consideration as beautiful, fresh, and worth keeping! What that means is
that great technical command is not easy, nor absolutely necessary to make
good images. Having fun doing it is crucial: "fun" in this sense is
synonymous to the exhilaration of being able to ride the bicycle for the
first time without falling - WOW, I've gained new ability and new insight!
I'm addicted!"

For me the salient point, is to have fun and enjoy the fruits of your labor,
as each print in it's own way is unique.

Hope this answers your question,

Don
Received on Mon Nov 14 20:27:20 2005