Cobalt Violet

Summary: Cobalt Violet is both an expensive and low-tinting-strength pigment that remains a part of the roster of paint colors that manufacturers continue to produce despite its drawbacks.

Graphic of Cobalt Violet Dry Pigment, Chemical Structure, and Chemical Formula

The focus of this essay is on the use of the element Cobalt as the basis for a pigment. While Cobalt Blue comes to mind the fastest, in this case, the discussion will be on Cobalt Violet. What is astounding about Cobalt Violet is the two characteristics that have so much going against its usefulness as a pigment for use by artists.

Cobalt Violet is both expensive and has weak tinting strength, especially when compared with other violet colorants. You are paying the price of a first-round NFL quarterback draft pick that plays like he is part of the practice squad. How did this pigment that should be a candidate for a Darwin Award still be an active part of violet pigments marketed today?

The history of Cobalt Violet does not provide a sufficient clue that deems it worthy of being included in artists' paints today. Someone known only by the name Salvetat documented the formulation of Cobalt Violet in 1859. During the same time period, Napoleon was engaged in war with Austria to help Italy gain independence. Too bad Salvetat was not focused on creating a red hue because it would have dovetailed nicely with honoring Napoleon’s victory against the Austrians in the Battles of Magenta and Solferino.

However, Salvetat had a good reason in the mid-19th century for making Cobalt Violet. “The first cobalt violets used were composed of cobalt arsenate. This highly toxic compound is now rarely used. Instead, most current cobalt violet hues are nontoxic and are made from either cobalt phosphate or cobalt ammonium phosphate.”  (Cameo website) 

We know from our general knowledge and previous Syntax of Color essays that arsenic compounds are highly poisonous. Cobalt Arsenate and other toxic colorants repeatedly raise the question as to why some of the most dangerous chemicals come to be used as pigments for artists to use.

Turning back to the key material, cobalt used to make Cobalt Violet, appears to have an expansive usefulness in our world today. Cobalt (Co with atomic number 27) is a metal extracted as a byproduct of copper and nickel mining. Cobalt is a key ingredient for making lithium-ion batteries, jet engine superalloys, magnets, and in medical devices that employ radioactive cobalt-60.

None of the useful applications of cobalt supports its justification for use as a pigment for art materials. It appears that just like many other historical pigment names and materials, it hung around in the inventory of art material manufacturers so long that it became an unnoticed fixture in the catalog of paints available for sale.

Most artist-grade lines of oil paint maintain Cobalt Violet PV14 in their inventory.  When compared in price to Ultramarine Violet PV15, a close “relative” to Ultramarine Blue, the price difference is astounding.  Cobalt Violet is sold anywhere between $29 USD and $84 USD, while Ultramarine Violet is sold in a range between $12 USD and $20 USD.

 Acknowledging that the hue and color bias of Cobalt Violet and Ultramarine Violet pigments are different, it is still difficult to justify spending 2 or 3 times the amount of money to purchase Cobalt Violet.  However, without doubt, several artists will argue that the cost is worth having a pigment with the characteristics of this secondary color hue.

Violet pigments, in general, are an odd lot. Most of them are warm-biased, leaning toward red rather than blue, so if an artist wanted to assemble a palette with a blue violet that resides in a color wheel between blue and violet, they would be hard-pressed to find a single pigment color that fulfills that role.

Of course, an artist can always revert to creating violet with blue and red and tailor it to be warmer or cooler using more blue or red or even using a complement to reduce its chroma.

Future essays will continue to explore various hues, and no doubt, Napoleon is sure to come up again in relation to the time period or fabrication history of another historical pigment.

The Syntax of Color