water gilding

[Norman Watts <Norman_Watts@zzzzzzz>]

So, I've been reading up on oil gilding and water gilding. Oil gilding
seems simple: cut your letter, paint on a thin layer of size, let it
dry pretty darn well, lay on the gold, pat it down with a mop brush,
when fully dry smooth it and clean it up with a slightly stiffer brush.
Wash it and go. My results look acceptable.

Water gilding is all alchemy; sanding the object, apply a finely tuned
gesso, followed by a special bole, sanding to about 600 grit, then
applying the leaf  by an ulcer-inducing technique. But burnished it is
supposedly more brilliant than oil gilding.

When I cut letters into slate (which I can't polish better than about
600 grit, so that means a surface smoothness similar to the sanded
gesso/bole surface mentioned above) and I then apply the oil-based gold
size (which when almost dry seems to give a very smooth surface too)
shouldn't the surface roughness be at least similar to the water gilded
material? I would imagine the oil size is too dry to work its way up
through the gold leaf, or to contract and induce surface microscopic
irregularities.

In other words, it is not clear to me at all, why water gilding gives a
more brilliant shine. I haven't actually tried the water gilding myself
to see if it is truly so. Can someone please explain?

n

Norman Watts, Ph. D.
National Institutes of Health
50 South Drive, Rm. 1509
Bethesda, MD 20892-8025
Phone: (301) 402-3418
Fax: (301) 480-7629