09/15/2008    |    Devlog    |    BSharp    |    Discuss

If you’ve ever taken an art class (especially a painting class), you’ve probably heard the phrase “never use black.” It is the mantra of high school art teachers everywhere.

Years ago, while showing my latest illustration project to one of my classes at the art college where I teach, a student asked “did you use black here?” pointing to the darkest spot in the painting. “Yes,” I replied. “Aw, that’s too bad,” he said, “you should never use black.” “Why not?” I asked. He did not know, but he’d heard it from other teachers and so, of course, he believed it. Certainly I’d heard it too, from high school through college, and always with a different explanation – most of which made no sense.

Rembrandt used black. Degas used it. Leonardo too. In fact, all of history’s greatest painters used black. I’m stumped to come up with someone who didn’t. Knowing this bit of information is confusing, isn’t it? Who’s right, Rembrandt or Ms. Meadows from junior year 5th period art class?

The best explanation I’ve heard for this statement is “never use black alone to create shadows in a color painting.” Here it has context that gives it meaning. In other words, if you’re painting a cast shadow from an object onto a white tablecloth, merely mixing black with white for the shadow shape won’t yield a very accurate or appealing result. Shadows, it seems, are not just darker valued instances of the local color of something. If they were, then color-tinting a black and white photograph (as is the technique of certain Hallmark cards) would yield results indistinguishable from color photographs. Yet this is not so, right? Shadows are darker valued, it’s true, but full color images clearly have more going on in them than just darkening up the darker areas with black.

So, just what is going on in the shadows of full color images besides a value change? Well, let’s assume for the sake of argument that all color in a scene comes from two sources: local color (the color that an object actually is) and light. In our example of the cast shadow on a tablecloth, our local color for the cloth is white, right? If our only other source of color is light, then where might colored light come from that would influence the color of our cast shadow on the white cloth? Would it come from the sky? The sky isn’t just a big blue object, after all—like a painted wall—it’s a big blue luminous object. It is a light source throwing blue light down onto our world like a blue sun. It’s a dim blue sun, however, so its light cannot be detected wherever actual sunlight shines—it’s far too dim to compete with sunlight—but only where the sun isn’t, like in a shadow. Also, any object receiving sunlight in the scene becomes itself a light source, dimly shining (or “bouncing”) light into the scene, light that is tinted by the object’s color.

So, in our tablecloth scene we have a very strong light source (sunlight) and lots of dim colored lights whose effects are only visible in shadows. This is why you don’t merely mix black together with an object’s color to make shadows; it is a much more complex mixture of color than that.

“Seven Suckers” by Wayne Thiebaud

At FLS, we always use color in our cast shadows rather than the default gray of software. We want to provide a rich, colorful experience for the user and not a color-tinted black and white experience. (Note that the cast shadows in the sails are purple and not gray.)

Black, in fact, is an AWESOME color—just ask Rembrandt (color theory states that black and white are not technically “colors” because they lack the property of saturation, but meh). The only thing as powerful as black in an image’s palette is white. In art college, I had a teacher who asked us to save our darkest darks and whitest whites and use them wisely and deliberately (this was great advice, btw). In a way, our brains “care” more about the value of a color (that is, a color’s brightness or darkness) than they do about its hue. We see value contrasts more readily than we see color contrasts (this probably maps to survival somehow). In the world of image making, this means that the value breakdown of an image is a powerful thing and that if you take it into consideration during the image making process, you can add punch to your imagery. So Professor Jean Blackburn was right, “save your whitest whites and darkest darks and use them wisely and deliberately.” By all means go ahead and use black!

Edgar Degas, Aux courses en province (At the Races in the Country), c. 1872

09/15/2008    |    Devlog    |    BSharp    |    Discuss