> I am looking for a place to get sizing supplies, photo gelatine, pumice
> power, and starch. Do I have to go to a photo supply company. SO far I
> have tried the local supermarket but my results are bad (maybe it's my
> technique and not the supplies). I am tring to size glass and wood to
> use as a base for cyanotypes.
I would think that Knox unflavored gelatin or most any good brand of food
grade gelatin should work fine. I used spray laundry starch for my first
experiment with carbon printing, and got better results than I had
expected. You should also be able to get potato or arrow root starch in
powder form at the grocery store as well. I don't know of a source of
pumice at the grocery store (abrasive cleaners maybe), but you should be
able to get this at a hardware store or art supply shop. If you are using
the pumice as an abrasive which I am assuming since I don't know of
another use, you may want to try asking for corundum, alumina, or powdered
abrasive. Jewelers rouge might also work, but tends to be more of a
paste. Don't know if this will help.
I've never tried sizing wood or making cyanotypes, so my suggestions about
this should be taken with an appropriate grain of salt. I am under the
impression that the cyanotype needs to be partially absorbed by the
substrate so don't know what the sizing requirements are. Perhaps you
might want to try sealing the wood with a commercial wood finish. A
varathane or shellac might work. Getting the gelatin to stick to glass or
plastic is a bit more problematic. There is a formula for a gelatin
subbing layer in Crawford's, Keepers of Light book under the Collotype
section. Basically, treating the plate with a very dilute gelatin
solution improves the likelyhood that the gelatin will stick to the plate.
Hope this helps. Let us know how your experiments work out.
- Wayde
(allen@boulder.nist.gov)