Quote Originally Posted by dmax
I have just begun experimenting with sizing papers with gelatin. Upon drying, I see minute sparkly things embedded in the gelatin, which show through in the final prints (cyanotype and Van Dyke Brown). The sparkly stuff shows through clearly and seem to act as a resist to the sensitizer coating.

Anyone know what these things are made of? Can they be filtered out somewhere down the process of preparing the gelatin?

I am using an experimental dilution of 1 packet Knox gelatin (7 g.) to 500ml distilled water. I find that the dilution is viscuous enough for sizing, but not so thick that the gelatin sets in the container.

Any information will be helpful.
Dmax,

First, you have "sparkles" which are grains of undisolved gelatin. To help dissolve the gelatin better always let the gelatin bloom and dissolve before heating.

Second add about 50 ml of grain alcohol for a half liter solution of gelatin. This will aid in dissolving the gelatin.

Third if you are going to gelatin size, use a about a 3% solution of gelatin.

Fourth, always weight the gelatin in the packets as there may not be the quantity of gelatin marked on the packs.

Fifth, you don't mention why you are sizing paper for these processes to begin with. Normally for VDB or cyanotype you don't need to gelatin size if you are using a "good" paper. Why do the extra work if you don't need to?

Don Bryant