Question asked 2018-10-05 10:18:03 ...
Most recent comment 2018-10-05 17:45:16
Over the years I've had several people give me boxes of old pigments they no longer want.
1. One box dates from1970s, NYC. It includes labeled jars of lead white and Naples yellow (the latter genuine, I presume). There are also many unlabeled jars of beautiful, turquoise colored pigments in various shades, akin to rich versions of dioptasio or malachite – but I'm doubtful malachite or dioptasio were commonly sold in NYC art stores in the 70s. I'm thinking they are more likely some other copper color (and should be handled with caution). Any thoughts?
2. Another box contains pigments bought at a tiny Italian color shop in Perugia – wrapped in wax paper with scratchy handwriting to identify them, not always legible. A bright yellow pigment is "Cromo", so I presume it's genuine chrome yellow and should be handled with caution? Another color is bright green, the writing something like "vinyulto" (very hard to read) – any guesses? An orangey red that looks like vermillion is labeled "scarlatto"– any idea what exact pigment the term scarlet refers to?
3. Finally, one box contains about a gallon of a fluffy black pigment, some sort of carbon I presume, maybe lamp? One of my least favorite colors. I could drop it off at a hazardous waste disposal day but we rarely have those where I live. Is it okay to just throw away or scatter carbon black in the woods?
Thanks. And I'm not taking anymore boxes of old pigments!
Answers and Comments
Honestly, there is really no way to know for sure with
unlabeled jars and vials of pigments. The lead white is certainly basic lead
carbonate if purchased from NYC Art supply as they would lead prime canvas and
sold their own lead white primers and paint. The Naples is probably lead antimonite
but I have analyzed some samples of Naples yellow from the 60s that turned out
to be mixtures. Other samples from W & N and Permanent Pigments and others
were the genuine article. I would be surprised if the turquoise pigments are
copper based as I do not really think that malachite and others were sold in
the states. As to the other boxes, it is difficult to know. Earthy colors are
likely what they appear to be. I have received small unlabeled vials of colored
powders and they turned out to be pigments used in painting china and were not
suitable, or at least not commonly used, for easel painting.
This brings me to how to tell what you have. You would need
to either do Polarized Light Microscopy or more advanced analytical techniques
like x-ray fluorescence, or even x-ray diffraction. Unless you are already in a
museum setting or experienced with PLM, it is just not worth it.
So in the long run, it is probably best to assume that each
pigment is the most poisonous possibility given its color. True emerald green
(copper aceto-arseniate) was still being sold in the 1960s. I would not use
pigments of unknown composition in one’s artwork. With this in mind, you can
either keep the vials in a safe place or have them disposed of properly by your
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