U of S | Mailing List Archive | alt-photo-process-l | Re: two questions about gum

Re: two questions about gum

On Tue, 25 Sep 2007, ryberg wrote:

I have noticed that my Daniel Smith Perylene Red stains the margins fairly heavily EXCEPT when it is the first layer. Is this kind of behavior common? Am I missing something? It took me quite a few prints to determine this since I have been printing that layer 2nd or 3rd and bemoaning the stain. Then I realized my 10x10 test chart showed no stain and made a print with the Magenta layer first--no stain. I am printing on unsized Fab Aristico.

Charles, I think that's the answer. An unsized paper has a light sizing from the making and/or the nap pressed down from the rolling, whether hot or cold press. One or both of those conditions permits your red to print well on "unsized" paper.... I would expect any color that's printed other than first coat on unsized paper to be cranky, but some are probably easier than others.

The first wash raises the nap and washes off any remnants of size, rolling, etc. that linger. Have you tried other colors second or 3rd? I'm not saying all behave the same, but suggesting why any coat may work on unsized paper when it's first, but not later.


On a related topic: After determining the exposure time and curve for each of the three colors I made a test print which was WAY too dark. Cutting the exposure time by nearly 2 stops helped. Katharine Thayer confirmed off-list that it is customary to have to cut back, though if I remember right she suggested using less pigment rather than cutting exposure. Is there any rule of thumb for cutting either the pigment or the t> Thanks. Charles Portland, Oregon