U of S | Mailing List Archive | alt-photo-process-l | Re: a few notes on my first few gum prints...

Re: a few notes on my first few gum prints...


I never use a second brush for smoothing. First, when you are doing multicoat, the several layers will tend to average any irregularity.

And second, with a hot climate like we have in Madrid, the coat will be almost dry when I finish covering the paper with the first brush anyway, so a secon brush would get stuck to the gum. At first I triend this approach but it was worse. When it is 30 centigrades inside and 20% relative humidity and you are attempting to coat a A3 size surface you don't have too much spare time for smoothing, if any. Of course in wetter climates this can change.

What I do when I feel that I'll be having coating difficulties is to wet the paper slightly before coating, as Geoff suggests, or mix some additional water in the emulsion.

As for brushes, yes you definitely need something with spring. I use Spanish Escoda brushes 2 inches wide with natural hair (Chungking hog bristle, actually). The ones with synthetic thin hairs have such high capillarity that the gum mix will stay mostly in the brush, and won't release it easily so you will need to load them much more.

Your second image BTW is very good :-)

Tom Sobota
Madrid, Spain

On Sat, Jul 4, 2009 at 8:36 AM, Paul Viapiano <viapiano@pacbell.net> wrote:
Hi all...
First of all, thanks for all the suggestions and comments on my first tricolor gum. It was definitely a good learning experience for me.
There are a few things that I noticed while working that I hope to clear up and solve.
One, is the use of hake brushes. I've been using the inexpensive variety found at the typical art store, about $2-4 each. Coating is difficult with these because there is absolutely no spring to them, they just go limp and the hair goes every which way even brushing lightly. I know how to coat pt/pd and am always successful when coating that emulsion. Gum, although more viscous than pt/pd should still flow on quite easily.
I know that the gum coating should be on the thin side, and my guess is that for a 4x5 print I should be using approx .5 - .75 ml of solution, but those hake brushes are horrible, very hard to get an even coating, at least consistently for me.
I'm very tempted to try a synthetic watercolor wash brush as I use for pt/pd (DaVinci Cosmotop). Expensive, yes, but the perfect brush for pt/pd. Just a dip in distilled water, a shake or two, and it's good to go. I bet it would really make for a nice smooth, even and just-right gum coating using the same technique.
Here's something else...I notice that Sam Wang, in his gum article on Unblinking Eye, brushes on his gum coating and doesn't use another dry brush to smooth it. I'm thinking of trying this as well, as long as I can get a really smooth, even coat down with a good brush.
One of the things I noticed was that while burnishing my coating with a dry brush, it started getting very grainy looking. I'm thinking that I could keep the smoothness if I just brush on once, nice and thin, and don't use another brush to burnish and dry.
Today was a disaster...I started on another tricolor print and upped the ratio of pigment to gum, to get darker colors and it all devolved from there. It happens, I'm experimenting...this has all been seat-of-my-pants stuff but now I need to do a few test strips with a consistent pigment/gum ratio to get a good starting point and figure out the smooth coat/non-grainy stuff, too.
Comments and criticisms are most welcome. I'll report back, if y'all don't mind, on my progress and findings...
Happy 4th to everyone here in the US and much thanks to all who weighed in from around the globe as well...