Further than red, but not quite as far as grey. The color blue (along with grey and other subdued colors) evokes a feeling of distance in a painting, while reds, yellows, and other bright colors feel much closer. This, along with other basic color theory, is something every beginning art student learns. Not every art student will take the next step and ask, “Why?”
The answer to that is atmospheric diffraction and some neuroscience. When I tried to share that jewel of knowledge with my painting teacher, she didn’t seem quite so interested. It’s not too hard to imagine why: artists tend to look at the world differently than scientists. Historically, this has led to a great deal of name-calling and disregard for the other side.
People like me, who are artists and scientists both, see this squabbling as missing the point.
It’s tempting, as a scientific thinker, to disregard how colors feel in painting as a basis for choosing colors. We know, through science, that the color of an object appears less saturated and bluer the further away it is. Red wavelengths of light travel in straighter lines through atmosphere, while blue wavelengths tend to hit and scatter off the gasses and particulates. The sky is blue for this reason. Blues evoke a feeling of distance because the brain (by instinct or experience) knows that further objects tend to be bluer. Seeing a relatively bluer object is thus a visual cue for distance.
It’s equally tempting, as an artist, to ignore any science involved, because you paint by feel. It’s a rare artist that runs diffraction equations to figure out what color to dab on the canvas. I suspect that my professor didn't care about diffraction because it felt too abstract and irrelevant to the actual painting process.
It’s perfectly fine to have these two viewpoints. The problem arises with the conceit that they are incompatible, when they are, in fact, complementary.
Why should the scientist develop a feel for colors? Because we live in our brains, and our brains are best at generating relative instead of absolute data. We are creatures of our bodies. If you want to paint a picture competently, develop and then rely on your internal color sense. Spend the time to understand how art can be visceral instead of intellectual. Good color sense improves the quality of your paintings, if not the emotional content. (This goes for other artistic disciplines, like music.)
Why should the artist understand the scientific backing? To navigate the unknown. We don’t always paint from life. Sometimes, we paint from several subjects at different times, or a subject in suboptimal conditions. Every time you need to estimate or make something up, having a grasp of the theoretical will help. This is especially important for fantasy and concept artists. Even for artists that paint only real things on earth, just knowing how things work can be a great help.
If anything, the preference for one method or explanation over another should be a place for curiosity and investigation. My painting professor looks at the world (and painting) totally differently from me. Her decisions about what paint goes where are internal, based on her feelings. I tend to frame things in terms of the big picture. Yet, despite our differences and no matter how “wishy-washy” it sounded, her advice and critique for me was always solid and worth following.
There’s a lot about art that I’ve discovered over the years that is intriguingly explained by physics, neuroscience, and evolutionary adaptation. That it was initially couched in “artsy” and “irrational” terms didn’t make it any less true. Yes, blue does feel further away than red. Some yellows are cold. You do have to love your art unconditionally, and sleeping on it does help.
Artistic and scientific people do think about the world differently, but it’s not a problem. (It’s also not the only way to think.) Instead, it is a resource. Approach a new viewpoint with an open mind and curiosity, and you will find that there is much to learn.