Max, The gilding bole used to be called
Armenian Bole because it was originally extracted from Armenia in different colors. The color of the bole is very important, as it allows the gold leaf to take on subtle but necessary hues and shades. Many different countries have contributed significantly to the history of frames, each with its own sources of colored clay, which resulted in specific frame colors.
If you plan to restore frames or other gilded surfaces, the color of the clay is paramount to your work. The clay beneath
Italian Renaissance frames was a luminous orange—no longer available today. Some may try to mix different clay colors, but modern sources tend to be too dark and even off-target.
French frames typically feature a red clay applied over a yellow clay. The clay is colored in mass and sold in
dry lumps or
premixed mud. The wet clay does not contain
RSG; it is simply mud.
Today's available colors are as follows:
- WHITE (more like a light gray, off-white)
- YELLOW (similar to a brownish ochre)
- RED (closer to a sienna shade)
- VENETIAN GREEN (quite pale)
- BLUE (a light bluish-grayish tone)
In my youth, I worked with much more vibrant colors that were closer to their names. And now you want to prepare your own clay out of
powdered ceramics mixed with graphite? Good luck!
Grasso can be burnished to a high degree. Even acrylic paint over gesso will work if you are not obsessed with perfection.
Gilders' bole is slightly different from
whiting (gesso), but technically, it is a
thinned-down, colored gesso.
Why would you want to prepare your own bole starting with poor-quality clay? Essentially, you need bole for its
consistent colors. It does not contribute to gesso’s ability to compress, which is essential for achieving a well-burnished surface.
Adding a bit of
alcohol to gesso and bolus is not for aesthetic purposes. Alcohol breaks the surface tension in gilding water, resulting in
clean gilding. In gesso, alcohol helps eliminate air bubbles and drives them to the surface.
Trapped air bubbles in gesso are responsible for pinholes, which are a nuisance to repair.
Once a pinhole appears, it cannot be removed, no matter how many layers of gesso are applied, or how much you wet and rub the spot with your fingers. You must
open the hole down to the bare wood, apply
putty, and then gesso again. In my opinion,
alcohol plays no role in preparing or painting bole.
Gilders make a
big fuss (almost like voodoo) about their craft, discussing
rigid, controlled recipes involving distilled water and precise temperatures (100°F, for example). But think about it for a moment—if gilding today requires all this precision, how was it done five or six centuries ago, during
Cennino Cennini’s time?
In fact, gilding is very similar to
cooking. A skilled cook creates exceptionally flavorful dishes simply by
tasting and
adjusting things accordingly. Those who insist on strict recipes would be lost when
RSG, whiting, or clays change their formula.
In reality,
whiting comes from Canada or England, whereas gilders in
Louis XIV's era or
Cennino Cennini's time had no access to modern material sources like we do today. You need to know what you are aiming for and
test your results to get as close to that goal as possible.
For example, how well does
gesso hold to the wood when sanding? How well does the clay burnish after
painting a few layers on your finger and letting it dry? How easily can it be
removed from your fingernail when rubbed with a bit of saliva?
See what I mean?
RSG is not always of the same quality (nor are other materials). What you find in
Paris is definitely different from what I can find in
New York or
Ottawa. If gilders were truly
obsessed with formulas, they would become
victims of their craft.
More importantly, you should
develop your own formula and stick to it.
By the way, traditional
gesso was made with
animal glue, making it
both permeable and soluble. Most modern gilders use
acrylic gesso, which is
neither permeable nor soluble. I have never heard a gilder complain about this
huge shift in their craft.
I still use
old-style gesso. Occasionally (very rarely), I hear stories about a
talented dog or cat licking the finish off my frames if they were left unattended in an accessible place—because they can
sense the animal glue, which smells like
chocolate to them!
Those who use
acrylic gesso never get such complaints from their customers. So, straying from tradition
in a creative and intelligent way is not always a mistake.
