Hello to all, Glass cleaning has been discussed thoroughly on this forum. I have my own procedure that I have published on Denise Ross's Thelighjtfarm.com . Whatever the cleaning procedure one uses, I think that a piece of glass should be able to hold a vertical sheet of water without breaking up or beading. It seams reasonable that a surface that cannot sustain a sheet of water cannot support an aqueous emulsion or solution. Sometimes I get an entire batch of glass that will not hold a vertical sheet of water no matter what I do. Adding a wash in ethanol has no effect. Even a micro-etch in NAOH will not help. I conclude that my entire batch of glass is not usable due to something inherent in the glass. I remember,years ago, running across a publication from KODAK discussing the quality of glass required for dry plates. I wonder if anyone is familiar with any glass "standards" employed by the old glass plate manufacturers. Thanks, Bill P.S. Coating with only IR light is a great big PAIN. Poor depth perception! I have a hard time finding the middle of the plate!