Hi Ian,
Thank you for explaining a method of creating multiples in pietra
dura (as well as wood).
The original post that I was answering asked for suggestions for
micro mosaic construction, and since the method I explained is what
I intend to try, I posted it. I never claimed that it was
historically acurate (I know the epoxy is a thoughoughly modern
interpretation).
That said, there is a little more history that you might be
interested in…
Mosaics differ from micromosaics, in that:
“MICROMOSAIC: A term coined by Arthur Gilbert to refer to Roman
mosaics with the smallest tesserae, sometimes as many as 1,500-5,000
per quare inch.”
Laura Hiserote writes on her site about micromosaics:
“The elongated tesserae used in micromosaics are made of glass
threads (smalti filati in Italian).”
Another site defines:
“SMALTI FILATI: Filati means �thread� in Italian. Smalti filati
literally means thread tesserae. The opaque enamel is heated and
pulled out to make long thin strands shaped similar to spaghetti or
linguini. These are then broken into shorter pieces called tesserae.
These originated about mid 18th century at the Vatican Mosaic
Workshops.”
And the curator of the Gilbert Collection writes:
“Over a period of many years, 28,000 different shades of tesserae
were created. These were composed of an opaque substance which was
neither shiny nor brittle like former glass mosaics. While the exact
formula has been kept a secret, the Vatican calls the substance
�enamel�. �Persons who have never seen a mosaic made find it
difficult to imagine how with small bits of colored enamel the most
valuable paintings may be exactly copied.� [Begni, The Vatican,
1914, p. 501]. By 1770 most of the altar paintings by the great
masters were successfully reproduced in mosaic; to this day, most
visitors to Saint Peter�s do not realize they are looking at mosaics
and not paintings. Around 1775, some artists at St. Peter�s began
making miniature mosaics using exceptionally small tesserae. These
were the first of what we now call �micromosaics�. Initially, as in
larger pictures, the tesserae were all square or rectilinear in
shape, but methods were eventually refined so that individual pieces
could be shaped to appeared almost like brush strokes.”
(I think that the Vatican called them “enamels” because they had
added some tempering chemicals to make them “softer” and less prone
to brittle breakage, much like ceramic glazes or metal-compatible
vitreous enamels. But this is just speculation.)
Ian wrote:
It is possible to get square section glass rods and these would be preferable for your plan as you would get much more colourful and better looking designs rather than having 30 - 40% cement.
Can you really direct me to filiments in the 1mm or less diameter
size? To square a rod requires extra work, and I would think that
would make them cost-prohibitive. Where do you think could I find
them?
There really won’t be 30 to 40% cement around the circular glass rod
filiments – for example, take several same-denomination coins, and
lay them on a table, and push them as close together as possible
without overlapping. I didn’t mathematically “solve for the empty
space”, but it looks much more like ten percent. I’ll just have to
try it, and see how it looks. Hooray for experimentation!
Thanks for your posting.
–Terri