Quote:
|
Originally Posted by APCenter
Any way you slice it, genuine vermillion is a problem pigment. You're gonna play the devil producing a paint that uses real mercuric sulfide that handles well and still manages to be lightfast. Not to mention that it is quite toxic...
|
Both points about vermilion are incorrect. While this is often stated as a matter of fact by many artists, the research and the evidence does not prove it.
Lightfastness of Vermilion
Vermilion is not a fugitive color, but has a reputation for being lightfast despite the urban legends to the contrary. Vermilion (inorganic, red mercuric sulfide, PR106, Colour Index number 77766) is listed in ASTM D 4302 with a lightfastness category of I in oil and resin-oil.
Gettens noted that "it is remarkably unreactive with other pigments" (Gettens & Sterner, 1941). Some authorities in the past did not consider it to be a "permanent" pigment, because specimens have been known to darken. Numerous examples in paintings, nevertheless, testify to its stability, and samples have been observed to withstand exposure to sunlight for at least ten years (Eibner, 1926). Tests made according to ASTM D 4236 the standard for lightfastness resulted in rating it at the highest category of lightfastness.
The darkening observed in some specimens of vermilion has been attributed to impurities in the digestion liquor used to make vermilion with the "wet" process, which may lead to the instability of the red form of mercuric sulfide to revert to the black form. The native mineral, cinnabar, is not susceptible to such reactions. Rublev Vermilion from Natural Pigments is made in China with the "dry" process, which is known to make a stable form of mercuric sulfide (Gettens, 1993).
Toxicity of Vermilion
In regards to its tixicity, some vermilion compounds do not represent the health risk once thought. Recent results of toxicology testing of Rublev vermilion and cinnabar dry powder pigments bear this out. These are historical pigments that are compounds of red mercuric sulfide (HgS). The former is the synthetic pigment and the latter is the natural mineral. Their hues and undertones are unmatched by any modern equivalent pigments, such as cadmium red.
An independent laboratory tested the pigments for soluble mercury and lead metals, according to method ASTM D5517-03 in which a sample is placed in a dilute solution of hydrochloric acid, which is the method accepted for simulating the acids found in the human stomach and the principal route of entry of these metals.
The test results are less than 20 µg (micrograms) of soluble metal per gram of pigment. The acceptable levels for soluble metals in pigments before hazardous labeling is required:
Mercury 76 µg/g
Of course, as with any dry powder pigment, a NIOSH-certified dust mask should be worn when working with dry powder pigments to avoid exposure to dust particles that can irritate the lungs. The above test results do not mean that proper protection should not be worn when working with powder pigments (or any powders for that matter).
References
ASTM D 4302-99 "Standard Specification for Artists' Oil, Resin-Oil, and Alkyd Paints,"
Annual Book of Standards Vol. 06.02, American Society for Testing and Materials (1999).
(Eibner, 1926) A. Eibner, "Arbeitsumfang der Versuchsanstalt für Maltechnik an der Technischen Hochschule zu München,"
Technische Mitteilungen für Malerei 42 (1926), 4-12.
(Gettens, 1993) Rutherford J. Gettens, Robert L. Feller, and W. T. Chase, "Vermilion and Cinnabar,"
Artists' Pigment, A Handbook of Their History and Characteristics Vol. 2 (1993) 159-181.
(Gettens & Sterner, 1941) R. J. Gettens and F. W. Sterner, "The Compatibility of Pigments in Artists' Oil Paints,"
Technical Studies in the Field of Fine Arts 10 (1941), 18-28.
For more information on this topic, please read the thread:
Vermilion and Cinnabar Toxicology Test Results
Quote:
|
Originally Posted by APCenter
Naples yellow is pretty much as bad, simply because PY41 is very toxic as well, and modern convenience mixtures that imitate it are very rarely permanent.
|
Genuine Naples yellow, which is lead antimonate yellow, contains lead, which can be a health hazard if ingested. However, this does not mean that with proper care and good studio practice artists can use these substances without endangering their health. The requisites in avoiding risk is awareness of the risks, how exposure to these risks can occur and how to handle the materials responsibly. Convenience mixtures to simulate the hue of lead antimonate yellow cannot match it for its opacity, permanence and tints.
Re: Show us your palette colors and tell us why
Linear Mode
