Let’s explore another of what art material manufacturers sometimes refer to as “convenience colors.” This means a color that can be mixed by the artists but is available ready-made as a mixture, thus saving the time it would take to mix this by hand.
I have been interested in why the color Permanent Green Light ever became a standard in the line of paints most manufacturers produce today. In most cases the mixture is made of yellow and blue pigment to form a high chroma bright green. However, when diving a bit deeper, it become clear why this combination appears to exist for artists to use.
Historically, a color called “Permanent Green” appears and disappears from the list of colors in various art materials catalogs. The Devoe catalog dated 1875 indicates an oil color called Permanent Green. The 1924 Winsor and Newton catalog makes no mention of Permanent Green. In 1933, the M. Grumbacher catalog contains the color Permanent Green Light.
The desire to have green colors made from single or combinations of pigment mixtures has always been part of the inventory in modern manufacturing of art materials. From weak tinting strength greens like Terre Verte to sharp intense colors like Emerald Green, the quest to find solid, permanent green colors has been important to the art materials industry.
While the single pigments of either Chromium Oxide Green and Viridian would satisfy the green color space for artists, the cool bias of these two colors when mixed with yellow to make a color that resembles Permanent Green Light, yields a somewhat dull green, lacking the punch that is characteristic of Permanent Green Light. Grumbacher’s 1933 version of Permanent Green Light, Medium and Deep combines Chromium Oxide with Zinc Yellow and Barium Sulfate. Permanent Green Deep was solely Chromium Oxide. (This is yet another wrinkle in deciphering pigment history when a color like Chromium Oxide is recast with the name Permanent Green Deep. However, confusion is part of the allure of attempting to understand the history of colors and paint making.)
So, how do we get from a somewhat dull Permanent Green Light in the early 20th century to the vibrant Permanent Green Light we have today? The answer is to make it from yellow and blue. We are aware that a typical palette employing cadmium yellow and cobalt or ultramarine blue will not get us to the color Permanent Green Light. Scratch that idea. The key is to use a blue that does not have a strong red bias. Cobalt and Ultramarine Blue pigment have a strong red “spectral tail” in the wavelengths at the upper end of the visible light portion of visual perception.
The key is to use Phthalocyanine Blue and a strong but not terribly expensive yellow like Arylide to make the high chroma green. Many artists refrain from using or even having Phthalocyanine Blue on their palettes because of its overpowering strength. So, using Permanent Green Light is a way of having a safe method to obtain an intense green that has many useful mixing properties for ramping green up and down to paint foliage when a common complaint is that artists never have enough diverse greens to paint landscapes.
The universe of green pigments is a study unto itself. From pigments that are safe for cosmetic use to greens that are used to preserve wood and serve as insect and rodent killers, it is a history worth exploring. For now, just enjoy the last vestiges of summer when painting green foliage takes on warmer, brown and yellow tones.
The Syntax of Color