Humans can see an estimated 10 million different colors, and each of us perceives every color differently. I could point to a light-skinned tomato and say it is red in color, but someone else might say it is more orange due to a color deficiency or through a difference in color nomenclature as a result of culture. (Tomato, to-mah-to.) Culture and gender are other possible factors that affect color perception. Women perceive a greater range of colors than men do, particularly shades of red. To explain the reason for this difference, researchers in this area point to our ancestors. The men hunted for animals while the women, when not tending to offspring or the cave, sought out fruits, vegetables and insects, and these were identified and rated poisonous or safe based on color. Women also are the only ones who could have the rare and theoretical tetrachromacy condition: a fourth type of cone. The result of a mutation in the two female X chromosomes, tetrachromats can have either red, red-shifted, green and blue cones or red, green, green-shifted and blue cones. In theory, this should result in a “heightened” sense of color and a broader color space, but the exact effects are not known and difficult to pinpoint because most of us are trichromats and we cannot see what they see. It would be as though we were trying to see ultraviolet radiation. A tetrachromat describing what they see would be like describing the color of UV; we trichromats have no reference for that perception. Another unknown is whether the brain and nervous system, wired for three-color input, can adapt to four colors to put those cones to use.

Genetically, men are relegated to trichromacy forever. But there is some hope for trichromats: it is thought but not yet proven that when rods kick in at low light intensities, they may contribute to color vision, providing a small region of tetrachromacy in trichromatic color space.

In the late 1700s and early 1800s, Johan Wolfgang von Goethe penned poetry and dramatic plays, and his masterpiece was Faust (which spawned his less-successful sequel, Faust II). The German master poet and playwright also dabbled in painting and color theory, writing the philosphical treatise Theory of Color. Goethe’s theory was interesting, in that it brought an emotional element to color, along with a keen sense of observation. Different colors make us feel various emotions, and humans knew this well before Goethe was born. He just happened to put forth these concepts on paper.

Goethe sketched a color circle of paint pigments but did not place the primary blue and yellow opposite the other — as primaries normally would be, with complementary colors in between. (A complementary, or secondary, color in paint, such as orange, is a mixture of red and yellow primaries and therefore falls between them. A tertiary color is created by mixing a primary and a secondary and would reside between those.) Goethe extended the blue and yellow into a large triangle within the circle. Next to the color circle he drew various triangles that represented alternative possibilities for the internal triangle, with emphases on considerations such as brightness and intensity, the complementary colors or the sensual-moral point of view he explained as force, sanguineness or melancholy. His intent with the early color wheel was to show how the colors were “sensual qualities within the content of consciousness,” and to relate their effects on the eye and mind. On the yellow and red side of the circle, what he called the plus side, colors were considered warm and comfortable, but on the blue side, or minus side, colors had an unsettled, weak and cold feeling.

Colors have meaning to us and stir emotions within us. Culture and our individual upbringing, as mentioned before, may play a role in how we perceive color. A number of studies into this possible psychological connection have been done and continue to be done. By studying groups in isolated locations, it has been hypothesized that humans are most likely born with a basic set of responses to color, but as we age, certain preferences and perceptions come to be held, based on experiences and cultural practices. Culture and/or location could have an impact. For example, Marc H. Bornstein, Ph.D., of the National Institute of Child Health and Human Development, found evidence in 1973 that populations with a closer proximity to the equator have less ability to discriminate shades of blue, but culture played no role. He did find that some cultures’ languages did not lexically discriminate blue from green. Studies indicate that these languages make semantic confusions that mimic tritanopic vision (the inability to distinguish the colors blue and yellow).

Studies of memory indicate that memory can also influence our perceptions of color. In remembering a significant moment that occurred on an otherwise bland, low-contrast day, we may recall the sky as a richer blue, the sand whiter, the water a lighter crystalline blue, the wetsuit a more saturated royal blue, the shark a darker gray and the blood a brighter red. (If I may use a grim example.) These “memory colors” tend to have narrow gamuts (color ranges) toward the primaries and more saturation, and they develop from the combined memories of many observations. They also must have context, because that’s what defines them. A memory color is not “green”; a memory color is “grass.” It’s as though we have formulated a perception and laid it on top of the original image that is stored away in our brains, and that formulated image is the one recalled. Memory colors do not affect what we see in the present. They could, however, affect our preferences. Cinematographers more often than not adjust at least some color in a scene — making the sky richer, the grass more vibrant or the tennis ball more vivid — by selecting certain filter such as color grads or by making adjustments using Power Windows in the DI suite, hoping to jog the audience’s memories and tap into the emotions that are attached to them, but also to present what we generally consider “pleasing” images.

However, changing color in a scene by way of the lighting doesn’t work as well when it comes to the tricky human vision system. Say, for example, a scene calls for a smug mogul to slide a letter of termination across the board table toward the company embezzler, and it is lit with some 2Ks shining through blue theatrical or party gels. In our perception of the scene, neither the actors, the table nor the white piece of paper change colors to blue. There is built-in context in that scene: we know what a boardroom typically looks like, what color human skin should be and that the paper is white. Our vision system has the ability to adjust the “white point” (or the point in the CIE chromaticity diagram where all primary and secondary colors of the spectrum come together to form white) to better match the light conditions — in this case, toward blue. Our eyes and brains make the adjustment based on reference — for example, the piece of paper that we assume to be white from experience. Take that same piece of paper and look at it when it’s lit by warm, orange candlelight, then by a tungsten 10K, then by a hard HMI, and finally by daylight. To a first approximation, we see the paper as white no matter what color temperature the light source may be.

As you can see, there are many variables for cinematographers to consider if they are not seeing eye to eye with a production designer or director (who, unknowingly, may have a touch of color blindness). More importantly, there are just as many factors to consider when one is trying to record, emulate and display the tristimulus color space of the human vision system in other media, such as film, television and digital projection (see diagram). Trying to describe a color to someone can be difficult when you function within your tristimulus color space model and the other person functions within his or hers. Color spaces naturally do not translate very well to each other.