Full Spectrum

From The Wall Street Journal:

Color is to the eye what birdsong is to the ear: a primal communion between ourselves and nature. The elemental power of color radiates from van Gogh’s shimmering wheat fields; in celestial photographs from the Hubble Space Telescope; and in the Technicolor fantasyscape that bursts onto the screen in “The Wizard of Oz.” Color memories linger in my brain: the ruddy orange of a lunar eclipse; the electric pink of cotton candy; the sky blue of Venus Paradise pencil #27. As I write, a window prism casts a cheery rainbow-stripe that drifts with the hours across my ceiling.

Color perception, and our enjoyment of it, is part of our evolutionary legacy. The human retina is sensitive to wavelengths of light from about 400 to 700 nanometers. (A nanometer is one-billionth of a meter.) That spectrum on my ceiling is sunlight deconstructed, with violet at the short-wavelength end, red at the long-wavelength end and other visual colors positioned in between.

The retina not only fixes the bounds of the eye’s sensitivity, it enables us to distinguish one wavelength of light from another. Lining the retina are pigment-containing cells—“cones”—which are stimulated by light of either short wavelength (blue), medium wavelength (green) or long wavelength (red). The relative intensities of light shining upon this trio of receptors trigger electrical impulses within the nervous system that the brain amalgamates into a particular color. This remarkable sight apparatus has figured into the rise of our species from the outset, making color and its perception fertile ground for examination. (Trichromacy is absent in people with red-green color blindness, who are born with two functional color receptors instead of three.)

Adam Rogers has spent several years interrogating the manifold aspects of color and its consequential relationship to human affairs. His book, “Full Spectrum: How the Science of Color Made us Modern,” is an informative and entertaining account of his findings. A deputy editor at Wired and author of “Proof: The Science of Booze,” Mr. Rogers is a seasoned raconteur, unreeling an eons-spanning tale with skill, mixing in didactic material, interviews with experts and whimsy. His admittedly idiosyncratic take on the topic of color ranges widely over art history, geochemistry, physics, neuroscience and global commerce.

. . . .

Until recent decades, there were too few natural or synthetic pigments to accurately and durably render what we see with our own eyes. For example, certain shades of blue and red are difficult to make; the newest blue was developed in 2009, two centuries after the previous blue-pigment discovery. This aesthetic imperative, Mr. Rogers asserts, was a major catalyst for centuries of technological innovation, manufacturing and trade.

The book opens with a chapter on earth tones—reds, yellows, oranges and browns—that, along with white from chalk or calcium carbonate and black from charcoal or manganese dioxide, formed the muted color palette of prehistory. We venture into Blombos Cave, along South Africa’s coast, which was first occupied at least 100,000 years ago and, according to Mr. Rogers, is “the oldest paint-making workshop ever found.” Here and at other Stone Age sites, our forebears converted at-hand natural materials into pigments for body ornamentation and cave art. No chemists these prehistoric artisans, they nonetheless utilized available resources with considerable skill; indeed, Mr. Rogers suggests, they might have supplemented earth tones with “delicate blues made from flower petals, greens from mushed-up grasses, river-mud grays”—all since effaced by time.

Pliny the Elder, writing in the first century, describes “florid” pigments, such as vermilion, Armenian blue, dragon’s blood red and Tyrian purple derived from sea snails. The sublime frescoes of Pompeii, although faded with age, testify to the role of color as a visual emblem of wealth and status in the ancient Roman world. Sourcing raw materials for the decorative arts became a significant driver of both international trade and imperial conquest: Rome established far-flung mining operations to satisfy its demand for pigments.

. . . .

The Middle Ages saw further expansion of available colors for artistic and decorative works. A handbook from the 1390s contained recipes for five different pigments of red, six of yellow, seven of green and a variety of blacks and whites. Another medieval writer described pigments with which to dye horses to increase their value. During the 15th century, painters began blending pigments with linseed or other oils, yielding glossier, more multitextured surfaces than their predecessors’ egg-tempera works.

Scientific research into the nature of light and color during this period, most famously by Isaac Newton in the 1660s and Thomas Young in the early 1800s, paralleled an increase in the use of color in the arts, textiles and cosmetics. Through chemistry and random, if purposeful, admixing, the 1800s proved to be a banner century for the development of new pigments, such as cadmium yellow, arsenic green and the first synthetic organic dye, mauve.

Link to the rest at The Wall Street Journal (PG apologizes for the paywall, but hasn’t figured out a way around it.)

fresco recently unearthed in Pompeii
The goddess Victory from the Murecine complex, via Wikimedia

7 thoughts on “Full Spectrum”

  1. Funnily, women actually see more colors than men – and, can differentiate between closely hued colors far better.
    Approximately 8% of men are color-blind to some degree. Less than 0.5% of women are.

      • You’re score is just a bit of anecdotage: even if Linda got 1 or more it would tell us nothing about men and women as a whole. I’m another old man and scored 4 so our sample currently gives a male average of 2; lets see in Linda beats it. It also suggests that I need an eye test as I skipped last year’s one whilst hiding from covid.

        • I know that. Just having a bit of fun. I’ve also scored an 8 and even higher at different times. Depends on how many days away I am from the Solstice!

          • Yes, I realised that, and so was I.

            The serious point I took from this was the reminder that the colour you see depends on the colours next to it. I enjoyed watching the colour of a square change as I dragged it right or left: another little thing that gives the lie to “seeing is believing”.

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