H i. One doesn’t have to use gold foil, one can also use silver
foil under red transparent enamel. However the effects are quite
different, and I would suggest that you try both and see which you
prefer. The reason some prefer gold is that it makes the red look
richer, but on the other hand the silver foil is equally nice,
only different. Transparent reds over copper have a totally
different look. I would suggest that you try the Transparent red
over bare copper, over copper that has had a coat of flux fired on,
over copper (with a coat of flux) and silver and gold foills and
then decide which is best for the project on which you are
working.- We all have our preferences, and it is a matter of taste
as to which is “best.”—cheers. Alma