Intro to the purples
Mimicking ancient methods of purple dyeing with carmine and indigo. On the low hills south of Goshen, New York, a farm with a little flock of sheep hand dyes its own yarn. There is something beautifully real about seeing a snowflake dissolve in a steaming pot of wine red cochineal. They begin with a medium-dark cochineal and over dye it with an indigo to produce a violet, a secondary color.
The History of Purple
The word “purple” comes from the Old English word “purpul,” which is from the Latin “purpura” and from the ancient Greek “porphyra.” This was the name of the Tyrian purple dye manufactured in classical antiquity. In human color psychology, purple is associated with royalty and nobility because Tyrian purple was only affordable to the elite. Byzantine empresses gave birth in the Purple Chamber. Therefore, Porphyrogenitus (“born to the purple”) was the name of an emperor which gained his throne by dinasty and not by force.
Purples are the shades of color occurring between red and blue. On a chromaticity diagram, the line connecting the extreme spectral colors red and violet is known as the “line of purples.”
Some confusion exists concerning the color names “purple” and “violet.” Purple is typically defined as a mixture of red and blue light, whereas violet is a specific spectral color (approximately 380-420 nm).
Purples can be formed by mixing red and blue pigments, but the first truly violet pigment was cobalt violet, prepared in 1859.
Timeline of purple pigments.
Purples and magentas are “colors” we see, but they do not correspond to pure wavelengths of light. On a chromaticity diagram (a CIE Luv diagram), spectral colors correspond to pure wavelengths of light, and wrap from the top and left ledges. On the bottom right diagonal, the line connecting the extreme spectral colors red (630-740) and violet (380-420 nm) is known as the “line of purples.”
The first synthetic dye was discovered by a teenager in 1856, who accidentally made a purple dye that would soon become the height of fashion in Victorian England. William Henry Perkin originally set out to discover a synthetic alternative to quinine. As he cleaned up his experiments with aniline, he noticed a thick black residue at the bottom of a flask. After further experimentation with diluting the sludge, Perkin realized that the mixture could be used to dye silk and that the dye would retain its color. Until that point, purple dyes always faded fairly quickly. Perkin initially called his new dye “Tyrian Purple,” but it was later known as “mauve.” Mauve quickly became all the rage in English high fashion.
Purple and violet pigments
Under the microscope, the pigment tends to be in the form of irregularly-shaped, plate-like particles and broken crystal forms, which may include gas bubbles. The particles range in size from 4 to 50 micrometres. It is very clearly pleochroic and shows a variety of colours from red to yellow to pale lavender. Between crossed polars the extinction is dispersed and consequently the interference colours are anomalous; it appears to show second order green and possibly third order colours. Many particles do not extinguish but merely change colour as the stage is rotated. In non-plane-polarised light, the particles vary in colour from bluish-red to violet and become strongly red with the Chelsea filter.
The method of preparing this pigment was first published in 1859. It is made by precipitating a soluble cobalt salt with disodium phosphate, washing the precipitate and then heating it strongly.
This pigment, often called cobalt violet dark, is extremely stable; it is unaffected by most reagents and sunlight. It is reddish violet in colour, is transparent in oil, has low tinting power, and exhibits pronounced purple/violet metameric effects. It can be used in all techniques. It was not listed by Winsor and Newton in 1896, but was listed in 1928.
Cobalt arsenate or Cobalt violet light
Refractive index c. 1.71 to c. 1.79
The particles are rather irregular in shape, those over 4 micrometres are usually noticeably coloured, but small particles are almost colourless, they may appear slightly greenish with most achromats. They show good relief. Between crossed polars the particles are strongly birefringent, large clear particles may have a sharp extinction but others are likely to have an undulose one. Most of the larger particles can be seen to be pleochroic, pink to pale pink. The particles range in size up to about 10 micrometres. A few length slow rods may be seen and groups of three radiating crystals may be found.
Crown says that the pigment was discovered in 1859, Mayer says that it was used as a pigment from about 1860. Probably occurs mainly in watercolours.
Quinacridone violet
C20H12O2N2(beta)
Refractive index c. 1.62 to c. 1.64
In plane polarised light the pigment appears as pinkish rectangular flakes. Those flakes that are elongated are likely to be twice as long as they are broad and to be slightly waisted. Large particles often contain gas bubbles at their centre. The particles show low interference colours (possibly because they are very thin),and are length slow. The extinction is parallel. The size varies between about 4 and 22 micrometres. There is no noticeable effect with the Chelsea filter. Groups of elongated crystals showing higher interference colours are likely to be present.
The quinacridones were first made in the 1930s in a German laboratory. They were developed in America in the 1950s and Winsor and Newton say that the material was introduced in 1958.
Fluorite
Calcium fluoride CaF2 Cubic, n = 1.434
Under the microscope, fluorite appears as broken colourless or slightly greyish purple coloured particles, The whole particle may show colour, but the colour is often confined to part of a particle, and may take the form a distinct band. Because most achromatic lenses make colourless materials that have a lower refractive index than Meltmount appear faintly violet, pink or purple, particles that appear to be only slightly violet should be checked with an apochromatic lens. As fluorite has excellent cleavage, a number of the particles are likely to have flat tops, and as the cleavage occurs parallel to the octohedron, some of these may take the form of equilateral triangles. Particles showing conchoidal fractures are common. Fluorite is isotropic, and it shows good relief in a mountant with a refractive index of 1.66. The particles are often large and may be as big as 80 micrometres in size, though are usually in the 10-50 micrometre range.. As fluorite is mined, other minerals are likely to be present in a sample, these include, quartz, calcite, and various silica minerals.
Fluorite particles are often large enough to be seen clearly in a cross section. However, it should be remembered that in this situation the particles will be oriented much more randomly than when they are viewed as a dispersion where cleavage flakes are likely to have settled flat on the slide. In addition, the polishing will have cut through the particles and so created shapes that relate only indirectly to the forms that are present in the section.
Fluorite is found as cubic, more rarely as octahedral and dodecahedral, crystals. It also occurs in a massive form. The crystals have been found in almost every colour except red. The massive form occurs in brown, colourless, green and violet. The massive form, which includes both colourless and violet areas is called ‘Blue John’ and was thought to occur only at Treak Cliff near Castleton in Derbyshire England, but closely similar banded blue and white fluorites are now know to occur in China, Southern Iran, and Nevada USA. Blue John was used during the eighteenth and nineteenth centuries to produce a variety of ornaments including large solid ‘vases’. Good purple fluorite occurs in the Black Forest, Bavaria, Saxony and Silesia. Other forms of fluorite were used, as a flux, as early as the 16th century during the smelting of lead and copper. Most varieties of fluorite fluoresce when excited with long wave ultraviolet light, but some, including Blue John, are inert.
A violet pigment consisting of fluorite has been found on a number of fifteenth and sixteenth century paintings and works of art from Northern and Eastern Europe. The first examples to be found came from the Tyrol and Southern Germany, where there are particularly good deposits of purple fluorite, and date from between 1470 and 1520. Fluorite has also been found on some paintings from the Netherlands (fluorite is found in the Ardennes), as well as on paintings, polychrome sculpture, or wall paintings from Bavaria, Silesia and Hungary. All the works date from the first half of the sixteenth century.(Ashok Roy: National Gallery Technical Bulletin Vol 21. See also Purple fluorite: a little known artists’ pigment … Mark Richter et all Studies in Conservation Vol 46 No. 1 2001. pp 1-13)
Mactaggart, P. & Mactaggart, A. (June 2007) ‘Purple and Violet Pigments’ In: Pigment ID using Polarised Light Microscopy from: https://academicprojects.co.uk/purple-and-violet-pigments/
Purple Ocher Oil Paint
Rublev Colours Purple Ocher is manufactured from iron oxide earth deposits containing augite porphyry in the Lori province of Armenia.
Purple Ocher harmonizes perfectly with other earth colors and is impossible to reproduce by mixing colors. Purple Ocher has a deep red masstone and subdued purple tints that are workable paste color ground in linseed oil with a moderate to low oil content and long, slightly thixotropic body. Being an iron oxide, it is lightfast and is compatible with almost all other pigments on the palette.
Rublev Colours Purple Ocher mixed with black or blue furnish grays and chocolates and is most invaluable in neutralizing greens. We believe it will make an excellent addition to any palette and become a primary color in creating cool tints in flesh tones and landscapes.
Composition and Permanence
| Purple Ocher | |
| Color: | Purple |
| Binder: | Linseed oil |
| Additive(s): | None |
| Pigment Information | |
| Pigment: | Armenian Purple Ocher |
| Pigment Classification: | Natural inorganic |
| Colour Index: | Pigment Red 102 (77491) |
| Chemical Name: | Natural Iron Oxide |
| Chemical Formula: | Fe2O3 |
| CAS No. | 1309-37-1 37338-85-5 |
| Properties | |
| Code: | 702 |
| Series: | 3 |
| Opacity: | Semi-Opaque |
| Tinting Strength: | Average |
| Drying Rate: | Medium |
| ASTM Lightfastness: | I |
| Permanence: | A – Permanent |
| Safety Information: | No acute or known chronic health hazards are associated with this product’s anticipated use (most chemicals are not thoroughly tested for chronic toxicity). Protect yourself against potentially unknown chronic hazards of this and other chemical products by keeping them out of your body. Do this by avoiding ingestion, excessive skin contact, and inhaling spraying mists, sanding dust, and vapors from heating. Conforms to ASTM D-4236 |
For a detailed explanation of the terms in the table above, please visit Composition and Permanence.
Notes
Some separation of pigment and oil may occur in Rublev Colours Artist Oils and is a natural process when no wax or stabilizers are added to paint to prevent this from occurring.
All images of color swatches on this website are only approximations of the actual color of the oil paint. We have carefully matched the color in these pictures on calibrated color monitors to the actual color. However, your results may vary because of the wide variance in color monitors.
Color Swatch Note: The color swatch was created with a thick application (left side) of color and a tint (right side) made with equal parts of color and titanium white and applied on acrylic primed cotton canvas.
Drawdown Note: The image of the “drawdown” contains a pre-mixed paint film of 6 mils (0.006 inches) thickness applied to a standard test card to examine color consistency, opacity, and other qualities. The drawdowns show the full-color strength (mass tone) on the left and mixed in a 1:2 ratio with titanium white on the right. The bottom area of the drawdowns is scraped to show undertones.
| SKU | 820-702 |
|---|---|
| Brand | Rublev Colours |
| Vendor | Natural Pigments |
| Processing Time | Usually ships the next business day. |
| Color | Violet |
| Pigment Type | Inorganic, Earth, Natural |
