Artistic color interaction
Artists use the perceptual qualities of the eye to build color interaction in their pictures, using actual pigments to imitate the contrast-enhanced image that the eye would normally see. There is no light running inside the picture; there are just adjacent color spots. The eye believes it sees a blue shadow not because there is an object whose shadow side only receives the bluish diffuse light of the sky; it just sees the pigment reflecting an appropriate color. Perceptual interaction of the hued spots on a flat surface imitates the effect of real light interaction in the environment. And if some color is not entirely appropriate in the context, the eye – especially a trained artist’s eye! – will perceive that the color is “off”.
And so, finally, we are ready to understand the treachery of neutral gray.
All chromatic colors, no matter how grayish they are, always interact with each other’s hue, making their cool neighbor warmer and becoming warmer because of its presence (and vice versa), and they interact with saturation too. Grayer colors make adjacent ones seem purer (and vice versa). But anything from the achromatic scale cannot influence the hues of surrounding colors, because it does not have any hue or saturation. Because it has no saturation, and since no actual light is traded in the picture plane, there is nothing to tint it either! It only takes perceptual influence from adjacent colors without giving, and forms a hole in the colored picture. For an artist’s eye, such a hole is as good as a poke in the eye with a sharp stick – it ruins all color interaction near it.
Neutral gray and computer art
The only way to make a neutral gray with paints is to mix our whitest white with our blackest black. Real world pigments can’t give us a perfectly even spectrum, but we can get pretty close. (In fact, artists have cautioned against mixing white and black for centuries: it looks bad next to color, and if mixed with other pigments, it only makes dirt.) But the computer monitor is an instrument that does not use colored pigments; it is instead built to work with the receptors directly. Its three phosphors radiate three pure, narrow-frequency colors that activate the receptors right in the peak of their sensitivity range. The spectrum of monitor’s “white” is not uniform like the real world white, it is three-peaked. But the eye cannot tell the difference. And as such, the monitor (and television screen) is the only widespread device that can make us see true neutral gray, by stimulating all three kinds of receptors equally.
The outcome is disastrous. The monitor’s neutral gray is much more pure than any mixture of real pigments. The “hole” effect is much more vividly evident. It is augmented; it stands out obscenely.
“I can’t see it”
A lot of people claim to not see it. Chances are that you, the reader, also do not see it yet. There are two main reasons for it.
First, people just tend to not see. They “see” by giving names to things their eye perceives, and insist that a sheet of paper is white no matter what color the ambient light is: they perceive the actual color, yes, but they believe it is white even if the lighting makes it deep red. The “artistic eye” I keep mentioning is (in part) the ability to pay attention to the actual color, not to some symbol in the mind. Once you understand this, you will be able to see actual colors, rather than your expectations.
Second, a lot of people use bad or poorly-adjusted monitors that do not produce exact hues. On some monitors, neutral gray is rendered decidedly warm or cool. This offsets the perceptual effect for the owners of these monitors. Anyone with a better tuned monitor will experience a poke in the eye. In fact, a badly tuned monitor makes all colors wrong, so the problem is not limited to neutral gray.
There is a whole science behind tuning the color of a monitor, generally called calibration, but the best solution is to invest in a good monitor if you are going to work with computer graphics. Otherwise, nothing you make will ever print or display right.
What to do
If you are working with physical paint, it’s simple: never use black and white in the same mixture when working in color. Ultramarine mixed with burnt sienna makes a good base for a variety of non-neutral grays.
If you are working digitally, and are not sure, just avoid colors with their saturation too low (avoid having the R,G and B component values too close to each other). You can also use the HSV palette to gauge your saturation more accurately. The saturation should never drop below several percent, and if there are more saturated colors next to it, then even 20 percent may be not enough. Always tint the grays.
Pure black and pure white are found at the edges of both scales, chromatic and achromatic alike, and so they are compatible with both colors and neutral grays-but only when they are pure and unmixed.
Working en grisaille or in black and white is absolutely no problem, since achromatic tones work with each other perfectly. They only wreak havoc on chromatic tones.
For both physical pigment and digital color, the ultimate solution is knowing how gray works, and not just avoiding it, but using it to your advantage. That’s what we shall discuss next.
