Shades of Cool
Looking for the blues
Cyan is a primary subtractive color in CMYK (printers) translating as no red (00), full green (FF), and full blue (FF), i.e. hex code #00FFFF. Subtractive color spaces create color by taking light away, i.e. using color inks or pigment, and black is made by adding all 3 primary colors (cyan, magenta and yellow). In an additive color space, like a light-emitting screen, you make color by adding light of different colors so black is the absence of all color. A hex code is notation for RGB values in a base-16 system in format RRGGBB which can occupy values from 00 to FF. Cyan can be called acid blue, because its sharp on the eye, analogous to lemon’s acidity on the tongue.
Prussian Blue is a much darker pigment with a very faintly green undertone, named so from the French bleu de Prusse because it was discovered in the capital of then Prussia in the early 18th century. Prussian Blue became iconic for its use in Edo-period Japanese woodblock prints because it was lightfast, rich and intense compared to the previously utilised indigo. Being more costly than standard, naturally produced pigments in Japan in the late 18th century, Prussian Blue signified prestige and wealth.
Most famously, Prussian Blue appears in Hokusai’s Great Wave off Kanagawa prints which later inspired Van Gogh, Degas, and Monet to use ukiyo-e compositions, flatter color, silhouette and line in contrast to the realism-laden academic approaches of late 19th century Europe. Beyond being beautiful and my favorite blue, Prussian Blue is used to treat thallium poisoning, in dye degradation to remove methylene blue pollutants from fluid, for energy storage and even electrochemical water splitting. The aforementioned methylene blue interestingly is an antidote for potassium cyanide poisoning, and for treatment of methemoglobinemia (of which a symptom is cyanosis, blue skin).
The deep sky in The Starry Night comes from Prussian Blue, likely mixed with cobalt blue and ultramarine for depth. Note the blues radiating in value, getting lighter as they approach moonlight.
THE STARRY NIGHT (1889) by Vincent Van Gogh
Cobalt — is a divine colour, and there’s nothing so fine as that for putting space around things”
- Van Gogh’s letter to brother Theo
- Van Gogh’s letter to brother Theo
Cobalt blue is a lighter, less intense blue pigment made by sintering cobalt oxide with aluminium oxide, famous for use in Chinese Yuan-dynasty ceramics. Cobalt blue was rediscovered in Europe by Louis Thénard, friends with the scientist Joseph Louis Gay-Lussac who synthesized cyanogen. Thénard was asked by the French government to synthesize a cheaper alternative to ultramarine, which was obtained by grinding up the expensive precious stone lapis lazuli (kyanos). Synthetic (French) ultramarine is more lightfast than the natural and was known to Goethe as early as 1787. Ultramarine is adjectival, from French outremer which describes ‘ over the sea’ places like Afghanistan, which is where the lapis was sourced.
“Carry me home, got my blue nail polish on
It's my favorite color and my favorite tone of song”
– Lana del Rey in ‘The Blackest Day’
Ultramarine’s several famous shades include Marian Blue, used to portray the Madonna in art history, with an example below by Sassoferato.
Another example below by Palma Vecchio hangs in the King’s dressing room at Windsor Castle.
THE VIRGIN AND CHILD WITH SAINTS CATHERINE OF ALEXANDRIA AND JOHN THE BAPTIST (1528) by Palma Vecchio
More recently, International Klein Blue (IKB) was developed by artist Yves Klein and paint supplier Edouard Adam (who’s still in business in Paris) with a special ‘linking paint’ (resin binder) preserving true pigment color. That’s why IKB is so blue (#002FA7) and curiously was identifiable by colorblind actor Eddie Redmayne, who wrote his thesis in Art History about it.
IKB 191 (1962) by Yves Klein
Ultramarine pigment is also non-toxic alternative to the ‘phthalo blue’ (copper phthalocyanine) often used in dyeing blue polythene bags.
Copper Phthalocyanine (C.I. Pigment Blue 15:3). Do you ever feel…like a plastic bag…
Tonight’s final blue on my mind is Le Blue Asse, the particular ‘incomparable color’ of airy blue used by Genevieve Asse. I invite you to disclose to me the pigments used to obtain it, you will have my gratitude.
ORAGE (2006) by Genevieve Asse
More recently, International Klein Blue (IKB) was developed by artist Yves Klein and paint supplier Edouard Adam (who’s still in business in Paris) with a special ‘linking paint’ (resin binder) preserving true pigment color. That’s why IKB is so blue (#002FA7) and curiously was identifiable by colorblind actor Eddie Redmayne, who wrote his thesis in Art History about it.
Ultramarine pigment is also non-toxic alternative to the ‘phthalo blue’ (copper phthalocyanine) often used in dyeing blue polythene bags.
Tonight’s final blue on my mind is Le Blue Asse, the particular ‘incomparable color’ of airy blue used by Genevieve Asse. I invite you to disclose to me the pigments used to obtain it, you will have my gratitude.