There are many formulas for substratum, and if this one might be reactive
to what you are doing, I could look up others.
Everything is filtered and purified, etc. 100ml of water with 1g of hard
gelatin dissolved in 70F has added to it a solution made up of 380ml of
125F water with 1g of alum and 20 ml of sodium silicate (water glass). If
the SS is in powder form, use 5g with 400 ml of water.
Brush it on a warm 125F plate and let dry. It appears that if the plates
are stored after coating, it improves their effectiveness. I let them dry
at least a day. Before storing, re-rinse to remove excess sodium
silicate. Do not touch the surface.
I also cleaned the glass very carefully, rinsing in hot water, getting the
water to run off in a sheet then air drying vertically.
I used a dichromated gelatin coating on top and it adhered well enough to
make it impossible to clean the plates for re-use. Some plates overheated
and the gelatin shrunk and peeled from the glass. When trying to clean the
class there were little bits which could not even be ground off. I finally
examined the marks with a magnifying glass to find that the gelatin adhered
well enough to the glass to cause chips when it peeled.
Good luck
Greg Shattenberg
Shattenb@megalink.net