I have a new affliction with some gum prints. On a intermittent basis I am getting small black or very dark brown spots that appear when a freshly coated piece of paper dries. They are not visible immediately after coating the paper but appear during the drying process. Currently I am using Fabriano Artistico Extra White hot press paper sized with gelatin that is hardened with glutaraldehyde. Once the little spots appear they remain permanently, ruining the print in most cases. I am at a loss to explain the origin of these spots and wonder if anyone else out there has encountered this problem.

Are these spots independent of the pigment color you're using or are they happening with black pigments?

Are these spots independent of the pigment color you're using or are they happening with black pigments?

The spots seem independent of the pigment. I have had them come up with M. Graham Indian Yellow and Daniel Smith Deep Scarlet.

I have a theory about what may be happening. I was looking around my work area thinking about the problem and I suspect it may be my Badger Brush. I have been using badger varnish brushes to remove streakiness in the emulsion coat. I observed apparent rust in the shanks of the brush with a stain running down the bristles. It appears that the maker wasn't concerned about corrosion since it is a VARNISH brush. So it might be that rust particles are working their way down the brush into the wet emulsion with a stain spreading as the drying goes on (maybe). I will try a badger shaving brush with a wood handle and see if that cures the problem.

However, I will be grateful for any enlightenment available, in case my theory is just baloney :-)

Thanks,

jh