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| Some Common Blues Top row: Draw-downs showing transparency Bottom row: Tints From left to right: Prussian, Phthalo, Indanthrone, Cobalt, Ultramarine (all from Gamblin) (From The Artist's Magazine, October 2013) |
I've always been a fan of Prussian Blue. Although many landscape painters like Ultramarine Blue and Cobalt Blue for their skies, in my view these always seem a little too intense and need to be muted. Prussian Blue already seems more muted, more natural. It also greys down other colors in the landscape well, especially the reds, and produces a wide range of greens with yellows and oranges. And I love the way it mixes with earth colors. One of my favorite palettes: Yellow Ochre, Burnt Sienna and Prussian Blue.
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| Rain over the River, 12x16 Oil (Available) Prussian Blue is great for storms, too. Painted with Yellow Ochre, Burnt Sienna, Prussian Blue. |
In my recent demo for Eric Rhoads' daily series of artist demonstrations, I used Prussian Blue. Someone observed that the pigment is poisonous, and that I should be careful. Well, yes, it contains a compound of cyanide, but it is not poisonous.
A student of mine, Charles Eisener, who has a long history with pigments in the medical field, explained this to me, and with his permission, I want to share it with you. His qualifications: “Over a period of almost 50 years, I worked with dye powders and stains, solutions, solvents and chemicals that most folks do not even know to be part of our medical care system. Mutagens, carcinogens, caustics, poisons and potential explosives were all part of the mix.”
Regarding Prussian Blue, he writes:
Prussian Blue is a double iron salt complex with cyanide and is a commonly used pigment in many areas, including Histotechnology. I have used the pigment over more than 40 years in that capacity and have yet to see it labeled as a poison. Most safety references did not list ANY physical hazards associated with skin contact unless you are referencing the basic chemical "powder." Like many other chemicals, the bets are off when ingestion or injection is involved. Even flour can be a hazard when injected. Chinese white is a close chemical relative; after oxidation it also turns blue. Ferrous ferrocyanide salts are widely used in many product areas as pigments and carry no explicit hazards to the product user. Personally, the cadmiums pose far greater health hazards to the user than a worst-case scenario with Prussian Blue given the same type of exposure.
The cyanide is so tightly bound to the iron salt in this pigment that a reaction to the iron salts is far more likely than any potential exposure to what is left of the cyanide molecule. The other factor is that many manufacturers do not even use the ferrous cyanide salts for their "Prussian Blue." Some of the synthetic pigments are much easier to produce and thus much cheaper to include in the end product. As always, it pays to carefully read the labels, so you know what you are paying for, or being exposed to.
He goes on, more generally:
Our primary risk from chemicals, solvents, and pigments occurs during the actual act of mixing and applying paint or cleaning our materials and tools. Residual risks from artists pigments are very minute, particularly if due diligence is taken with disposal. Rinse water containing pigments can be precipitated and disposed of as a solid. Dried paint films are at very minimal risk of releasing cadmium. Far more heavy metals are released into the environment through household disposables than from artist studios. This does not mean we should not exercise caution, but rather that risks are quite relative. Some of the pigments currently in use show "unknown" under various risk categories on their official MSDS (Material Safety Data Sheet) forms. Nobody has done research to determine that potential risk. Does that mean it is safer than a cadmium color with known risk? Hardly! Should we not take more care with an unknown than with a known?
Many common food preservatives and colorants carry health risks if one cares to examine their MSDS data. OSHA guidelines mandated that gloves and face protection be used when weighing out sodium chloride, yet the cafeteria provided saltshakers on every table. Risks and safety are relative. Ingesting too much water or too much table salt can cause health issues or in extreme cases, death. So can too little! Safety is a relative term and simply implies the use of common sense and reasonable care based upon our current knowledge of the specific chemical/product.
Here in the US, we have labeling requirements. It pays to read the label and to know what we're painting with.
By the way, I am on the faculty for Plein Air Live. If you haven't already signed up, there's still plenty of time. You can find out more about Plein Air Live here.
