Weird Stuff About Light and Color

(No, this doesn’t end up being about philosophy. Once a decade I’m allowed to write about something else.)

Here, in no particular order, are some random weird facts about light and color:

1 - “White” is not a color frequency. It is what we see when there are a bunch of different color frequencies combined, across the whole spectrum. If you doubt it, find something that spins really fast, and cover the whole surface with solid blue, red and yellow segments. When it is spinning fast enough, it will appear white. (If you mix all the paints together instead, you’ll get a dark mush.)

2 - The colors we see are often not the colors that are really there. Try making a bunch of really tiny blue dots and really tiny red dots on a piece of paper, and look at it from a distance. It will appear purple, even though none of it is actually emitting the frequency of purple. Unlike our ears, which can simultaneously detect multiple sound frequencies at the same time (like several notes in a musical cord), in any one place our eyes can only “see” one frequency, and often our eyes fudge things and make us see a frequency that isn’t even really there.

3 - As one example of this, when we see a star, or something else burning, we see it as one color (e.g., white or yellow), when it is actually emitting many different frequencies. A spectrometer can tell us what elements make up the thing that is burning, because different elements give off different frequencies as they burn. (My theory is that our eyes and brains intentionally limit and “fudge” what we see, because if we could actually see many separate frequencies from one point at the same time, the way a spectrometer does, there would be way too much damn information for our brain to even process it.)

4 - Snowflakes are not white. They are clear. They are, after all, made of ice. The reason snow looks white is because countless tiny facets of the ice crystals are refracting and reflecting light from all directions, and all colors together appear as white.

5 - If you take all the frequencies, but add an extra dose of green (or, to put it another way, combine white with green), we call the result “light green.” Do the same thing with blue and we call it “light blue.” Do the same thing with red and … it’s “pink.” There’s no such thing as “light red.” (I’m still not sure if this has more to do with our language, our eyes, or our brains.)

6 - Silver is not a color. It is what we call something that is 100% reflective. A mirror, for example, is “silver,” but all it does is reflect other things, without adding or modifying the color of those other things. Likewise, if you look closely at a well-polished silver tea pot, for example, you will see that you’re merely seeing twisted, bent, distorted reflections of other things around it. A “silver” object in space appears black (except little white specks of reflected stars). A “silver” object in a completely blue room appears completely blue.

7 - The concept of “gold” as a color is weird. What it actually refers to is a surface that reflects other things around it (like silver), but which also adds a yellowish tint to the reflection. So “gold” refers to reflection plus a certain color. We don’t have such a simple term for something that is reflective but adds a tint of blue, or green, or red. Only yellow/orange.

8 - Our eyeballs automatically adjust the size of our pupils depending on how bright things are, but they also tell our brain that they are doing that. As a result, the amount of light hitting our retinas (the back of our eyeballs) may be the same in a dark room and in a light room, and yet our brain knows that one is brighter.

9 - When a camera aperture does something similar, changing size to control the amount of light being let in, it obviously does not tell our brain about it. So if we see pictures of a light room and a dark room, but with the camera adjusting its “pupil,” we can’t tell the difference.

10 - I will end with one that I still don’t understand. When it comes to using pigments—paint, for example—the three primary colors, from which you can create all the others, are red, blue and yellow. But when it comes to using light, the primary colors are red, blue and green. (People who do computer graphics, and also art with physical mediums, know this.) I still don’t get why one of the primary colors changes. What the poop?

(P.S. Some time I hope to make an animated video showing why rainbows look like that to us—the arc with different color bands—because it’s really dang cool.)

We now return you to your regularly scheduled mayhem.