David K. posts some interesting observations and questions. Apologies for the extensive quoting.

I think that silver tarnish is not caused by light, nor, strictly speaking by oxidation, but by a reaction with sulfur compounds. It is silver salts that turn black with exposure to light (as in photography), so possibly the final rich, deep, black of tarnished silver is a two-stage process: the silver reacts with sulfur and the silver (sulfides?) behave like the silver salts on photographic film, turning black upon exposure to light. Silver protected from the atmosphere by clear coats or changing varnishes doesn’t tarnish and turn black. Silver exposed to the atmosphere, as we all know, doesn’t take very long to turn black.

Vermillion pigment is still available, and still legal, and drop-dead gorgeous. It is toxic, but not spectacularly so if handled with some prudence and care. Fortunately, so far as I know, it does not contain arsenic (if it did, it would most definitely be illegal), but mercury. Probably about as toxic as traditional lead paints. Adrian card, on all the naive chinoiserie on my recent big Zell, used genuine vermillion for the red highlights.

Prussian blue can be a precursor to the manufacture of the deadly poisonous prussic acid (what we commonly call “cyanide”), but is not particularly poisonous itself. I’ve used it, and even in commercial paints called prussian blue, like the Ronan Japan colors, real prussian blue pigment is used, because it’s safe and relatively inexpensive. I believe that it may have been the very first synthetic pigment created by “modern” chemistry, and made its debut at almost exactly the time Mietke was active in Berlin. A recent single I made after the 1710 Hudiksvall Mietke has genuine prussian blue as its ground. I think that peculiar, and especially beautiful, greenish-blue one sees on so many 18th- and 19th-century Japanese Ukioye wooblock prints must almost certainly be prussian blue.  Here’s a neat summary article I found on Wikipedia. It is interesting that so far from being poisonous, it is used as a treatment to leach poisonous heavy-metal ions out of the body.

https://en.wikipedia.org/wiki/Prussian_blue

Just for the fun of it, I’ll post close-ups of the real vermillion and prussian blue pigments on our HPSCHD_L Facebook page shortly.

I love this stuff. My colleague and friend the artist Adrian Card in San Francisco has a lot of experience and knowledge of traditional pigments. As a display, he has a small LOCKED glass-fronted cabinet with several of the most beautiful, but most desperately poisonous and illegal-to-deploy pigments. There is nothing in this world quite as gorgeous as the rich golden yellow of orpiment, which IS an arsenic compound, and deadly poisonous. And there was Emerald or Paris Green, which is just dazzlingly beautiful, but was finally, I think, banned, because its use in gorgeous green wallpaper in the 19th century led to many deaths. Nobody in their right mind, at least in the arts, will handle either orpiment or Paris green.

owen




Andrew's post, incorporating quotes from Denzel Wraight, raises some questions for me.

>>> Obviously the varnish is used both to change the colour to golden and to stop the silver from oxidising.

Is not silver tarnish caused by exposure to light, rather than air?  Does the varnish in some way prevent a certain band or color of light from penetrating, thus preventing tarnishing of the silver?  (Is "oxidation" in silver the same thing as "tarnish?")

>>> HIgh material costs often affected decoration choices. The vivid Vermilion paint we see in French instruments came from an expensive pigment, and many instruments used what is often referred to as bole instead, a cheaper, but less brilliant red colour instead.

I seem to recall that Vermillion pigment was not only expensive, but also highly toxic.  Or was it bole?  I think it contains arsenic, and for this reason is difficult or impossible to obtain nowadays.  Is this correct?  Has modern science found a suitable substitute?  (Wasn't there cyanide or "Prussian blue" in some blue and green pigments too?  Being a painter, like being a hatter, must have been a risky profession in those days!)

>>> For example you can buy what is called green gold leaf, or lemon gold leaf, and so on. So gilding can have a wide range of effective shades.

I've not seen this, but I assume there is some alloyed metal used as a coloring agent?  Of course, pure gold is always the same color.  I would think the gold would have to be *very* thin to allow an underlying color to "bleed through" (in fact I would not have even thought it possible--it seems very opaque).  I remember when my instrument was being decorated, Pete insisted on painting the moldings before gilding them.  He knew there would be little imperfections in the gilding of the highly irregular surface, and wanted Vermillion to "peek through" in those spots.

dk
____________________________________


Owen Daly Early Keyboard Instruments
557 Statesman St. NE
Salem, OR 97301
http://www.dalyharpsichords.com
(503)-362-9396

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
Note:  opinions  expressed on HPSCHD-L are those of the  individual con-
tributors and not necessarily  those of the list owners  nor of the Uni-
versity of Iowa.  For a brief  summary of list  commands, send mail to
[log in to unmask]  saying  HELP .
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::