U of S | Mailing List Archive | alt-photo-process-l | Re: Ruined 3rd tricolor gum print! Grrrr...

Re: Ruined 3rd tricolor gum print! Grrrr...

You're right, Laura, in that if the layer is too thick you thin with water
generally. But Loris had other issues as well, IMHO.

Flaking can have several causes--too much pigment, too thick a gum layer
either by not brushing thinly enough or by putting too much on the print (an
8x10 requires about 1/2 tsp), and also too little exposure for the thickness
of the layer/darkness of the color. These causes become very apparent when
working with thick black layers with dense black pigment.

Since usually I am NOT fiddling around with too much pigment because I have
already determined how much the layer needs, thickness and exposure are what
I personally look at. And in Loris' case he is using paper negatives which
are slow hence the suggestion to use more dichromate. In my case with thalo
it is a fast pigment and I use diginegs and so I personally would look to
the thickness of the layer alone and thin it with water.

However, adding more dichromate does lower apparent contrast more but then again you are having to determine is it lower contrast or increased exposure? In Loris case if he is suffering contrast issues as well either a longer development or weaker am di will solve that problem. Thus you are back to adding water instead of dichromate.

As far as order of layers, I don't think it much matters. I usually do a blue first because I, too, register by eyeball over a light box. Then yellow then magenta. But sometimes I do magenta first. I never do yellow first only because of my registration process. What determines what order I do my layers in is that I usually do 6-8 large gums at once, and if a whole group needs a particular color mostly, then I mix up a batch of 8 tsp of that color and all the prints get that color regardless. Kind of assembly line style :)


Christina Z. Anderson
----- Original Message ----- From: "Laura Valentino" <laura@this.is>
To: <alt-photo-process-l@usask.ca>
Sent: Wednesday, September 24, 2008 2:58 AM
Subject: Re: Ruined 3rd tricolor gum print! Grrrr...

Christina Z. Anderson wrote:
Thus you could thin out the final layer and brush it on very carefully.  I
might thin it with, let's say, 2 di: 1 gum/color. This will make the layer
faster because of the increased dichromate and thinner layer but that may
help you even more.
Really? You thin out by adding more dichromate? Why not just water?

Interesting...just before this thread started, I had done a too thick
thalo layer which flaked...but I thought the flaking was because I had
mixed a new batch of gum which was a bit thick, so I'm considering
thinning it with water to see if that helps.

In that case, the thalo was the second layer, but when I've been doing
tricolors I put the thalo layer first. My reason for doing so is because
1. I read somewhere that that's how tricolor is done (I figured there must
be some reason, although I didn't know what) and 2. I register by eyeball
and if I use a light color for the first layer I can't see the
registration marks.