Pigment Palaver: Prussian Blue

Boy, July has just flown by, hasn't it? I realize it's been pretty quiet on the blog front this month, mostly because I've been busy finally getting some results from my research after almost a year spent tracking down and compensating for various systematic errors, and I'm usually left too tired to feel much like writing. I've also been in a bit of a rush up to a fortnight ago getting some artworks done for an Apollo 11 50^th-anniversary exhibition. (A topic for another time!)

Two weeks ago, however, we finally got all the paintings and other artwork finished, packed up, and off to the gallery, so I've been getting inspired and feeling like painting again. I've gone back and worked some more on a painting I started back in December, and due to painting the ocean in five different shades of blue today I wanted to talk about one specific color I used: Prussian blue.

Prussian Blue

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This dark, intense blue, also sometimes known as Berlin blue, Paris blue, or Parisian blue, takes it most-widely known name from the state of Prussia, whose capital was Berlin. (For those familiar with European history from the 16^th century onward the military exploits of Prussia are practically legendary, but I don't know how familiar it is to the average person nowadays.) It was invented in about 1706 by a paintmaker by the name of Diesbach (possible first names of “Johann Jacob”) and seems to have received its name sometime in the next few years, as it was being marketed as Prussian blue or Berlin blue by 1709.

Prussian blue has the chemical formula Fe^III₄[Fe^II(CN)₆]₃, and despite having a lot of cyanide groups (the CN groups) is completely non-toxic, and in fact is used an antidote to poisoning by certain heavy metals such as thallium. (It's even on the World Health Organization's List of Essential Medicines as a result.) Blueprints take their name from this pigment, and it's interesting as the first of the modern synthetic pigments. Although some synthetic pigments were used in antiquity, such as Egyptian blue, the knowledge of how to make them had been lost to time. European painters who wanted blue were stuck with either a variety of pigments that weren't particularly light-fast over time, or ultramarine blue made from ground-up lapis-lazuli, which was literally more expensive than gold. It's thus hard to overstate just how revolutionary Prussian blue—a light-fast, strong, and affordable pigment—really was at the time.

Of course, being light-fast and cheap are nice, but artists care about the color, and Prussian blue really delivers on that front. It was one of the first few colors of paint I picked up, so in my very first painting (below) pretty much all the blue (in the ice and snow) comes from Prussian blue. It works really well, even mixed with copious amounts of titanium white (as it's actually a very dark blue when pure), and really shows it versatility. In the painting I mentioned in the opening paragraph I'm using it in a completely opposite role, as the deep dark blue of the deep ocean, showing just what a wide range it can play and why it's so useful to an artist.

Prussian blue was the first of the modern synthetic pigments, and its discovery sparked a whole new era for painters, who are blessed nowadays with a range of synthetically-created pigments with colors, intensities, light-fastnesses, and cheap prices that the Old Masters could scarcely have dreamed of. And while plenty of the synthetic pigments created in the years since have faded away into obscurity, Prussian blue is still going strong. I've got a painting in mind to do in which Prussian blue will probably play a large part, as it's almost the perfect shade of blue to match one of my favorite animals—but that'll come in due time; I haven't even started it yet! All in all, if you're looking for a versatile blue pigment with an impressive pedigree and even lifesaving properties, you could do far worse than Prussian blue. A hui hou!