Kristy T - An Ink Stained reader e-mailed me and told me about another recipe to make a home-made gelatin plate posted by the Frugal Crafter here - A Permanent Gelatin Printing Plate. She uses glycerin mixed with the water & gelatin to create a printing plate that doesn't need refrigeration which is super. Kristy said she used hers for several months.
She also suggested keeping a little spray bottle with glycerin handy to spritz onto your paints for a longer open time. A super idea!