It is a mixture of PVA and PVC with additional surfactants and colour to
give it the appearance of gum arabic. It is this combination that gives
greater consistency in making gum prints than gum arabic.
Straight PVA will make a good first coat but appears to be uncontrollable
for the second coat.
Now if Gloy went off the market I would be exploring how to make that
second coat work. That would probably involve not too many tests on
standard surfactants. Once I have my new centre for alternative phorography
upand running, in September I hope, I will probably give it a go.
Incidentally from the 'gardening photography' standpoint if your local
stationery store sells paper glue that looks like gum arabic there is a
fair chance that that is just what it is.
Terry King