The art of the shadow: How painters have gotten it wrong for centuries

Those actually judging the art of the times probably didn't really know or care, as the illustrations were often done for social reasons at least as much as decorations. As the canon of "shadow science" increased, there would be more pressure to also please professionals who may judge your work and pass on the word. "Don't hire Bob, hire me, for he does shadows wrong. Here, I'll show you using candle light and these books...".

Pleasing customers and pleasing artists are often different things. Bach pleased artists much more than "customers" and thus made a middle-of-the-road salary despite being a musical genius. Mozart was arguably the same way, as he had some trouble keeping up with short-term fads.

Overall, shadows aren't the hard part nowadays, it's light that is. Global illumination and light bouncing back around that is. Though shadows ARE very expensive still.

Highly skilled artists don't just think in 2D — they really do imagine the 3D scene that they're painting. It's hard to relate to but people with a lot of drawing/painting experience can "feel the form", as they say, when they draw. But it's true that figuring out the lighting is still difficult even then.

I do want to point out that if you look at talented painters from later in history than the early renaissance, they don't make nearly as many mistakes as the ones in the article, although of course the lighting of imaginary scenes is still always approximated and simplified.

No form to it. You just have to draw lights and shadows as you “see” them. At end you have a well drawn curtain.

After awhile your entire perspective even outside of class changes. You naturally see lights and darks. Not just objects.

https://plato.stanford.edu/entries/nothingness/

Since the appearance of digital color, the common approaches to ink in comics have toned down because the painting process creates a competing value structure. The mixture of hard and soft shadow creates some jarring effects, so ink lines made "for color" are used more often just to describe form.

Where’s the tail come from, though? That’s the only bit I can’t figure out.

I heard this story as well and always suspected that it was an urban legend. I heard the same story about a Buddhist painter who intentionally added a poor brushstroke to every painting, to reflect that everything is imperfect and changing. Neither story makes sense in the context of Christian belief or Buddhist conviction. A Christian would have to be incredibly arrogant to think they had to take special measures to avoid rivaling the work of God — it would be hard to call such a person Christian. Similarly for the Buddhist. If they believed that everything that can be experienced has a certain characteristic, then it wouldn't be necessary to impose that characteristic on their artwork.

This is not true. Renaissance painters generally did strive for realism in perspective, anatomy etc. Sometimes they failed because it is really difficult. (After the invention of photography artists just use photo references which makes it a lot easier.) Sometimes they let artistic considerations take priority. In historical and mythological paintings they didn’t stive for realism in subject matter and overall impression, but they did strive to get the physical details correct or better than reality.

First of all, if you've got a sphere in deep space, its shadow side is going to be pure black, since there's pretty much no light bouncing around, and so there's no light to be reflected by the shadow side of the sphere. Now let's take an indoors scene: Imagine a room with red walls, a white floor, a single neutral (white light) ceiling lamp and a white sphere in the middle, what color is the sphere's shadow going to be? In the red-walled room, the shadows of the sphere would be subtly red — especially in the parts of the shadow where it's facing the walls more than the floor. That's because the light you see in the shadows of an object is light that has already been reflected from other surfaces in the room. This reflected light, in the case of the red walls, is red.

Of course in a more complicated scene you just approximate it. For an outside scene, you usually want to make your shadows only a bit darker and move your shadow color's hue a little closer to the color of the sky. But colors are difficult, you learn through experience really.

As you imply, the outcome is not always realistic. The reason is that the shadow would be tinted by the environment light. This is particularly apparent in desert environments or very sunny environments where the shadows can be a saturated blue.

An art teacher would tell you to paint from real life and look into the shadows and try to perceive the colors that are there. Paint those. Don't treat it as a chemistry problem.

But if you're wondering why Maxfield Parrish painted orange rocks with indigo shadows it's because in the absence of direct light (in the shadows) ambient light will fill in. And the sky, as an example, is a giant blue ambient light reflector, the grass a giant green one.

If errors of this magnitude were made in other aspects, say in face symmetry, the spacing of the eyes, etc, the resulting images would be not just uncanny valley territory but would look terrible.