Thank you very much. Mea culpa. It is Kuraray Poval R-1130. I am familiar with the information you suggested. Two or three years ago those guys (DPvisions and wildbillbugman) used Kuraray R-1110 that is not manufactured any more. They also mentioned that Bostick & Sullivan would sell it. At Kuraray they told me that R-1130 is the latest version. At B&S they did order it (R-1130) two or three years ago but forgot about it. They sent me a sample. By now they should have it on their site.
I followed those guys instructions , made 5% aqueous solution, coated the glass, baked at 225 degrees F, but cayanotype emulsion would not stick. That's why
I am asking if anyone else tried it instead of gelatin.