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

Re: two questions about gum

On Sep 25, 2007, at 4:54 PM, Katharine Thayer wrote:

(1) Charles, this makes sense; there's enough size in most watercolor paper as manufactured to keep the first layer from staining, but subsequent layers on unsized paper (depending on the paper) could well stain.

(2) I don't know that there's a rule of thumb for how to deal with this; people do whatever works for them, I suppose. If cutting the exposure time works, great. I can imagine that a drastic reduction in exposure might a similar effect to a reduction in pigment, but I've never tested that.
On reflection, I doubt the effect is the same; with underexposure it seems like you would be more likely to lose highlights than you would with a reduction in pigment.