What Color Is a Mirror?
If you’ve ever spent too much time thinking about a single thing, you’ve probably found yourself captivated by color. In focusing too much on how colors work–or spending too much time looking in a mirror, you might have asked yourself how colors in a mirror work. Chiefly, what color is a mirror? No, the answer is not “silver.”
A Perfect Mirror
When thinking about how color works, you’ve probably been faced with the whole thing about pigment and light. In short, the two define black and white in the exact opposite manner. White the color has no hue–which basically means it’s the “absence” of color. But when we’re dealing with wavelengths of light (which we are when it comes to a mirror), white is the presence of all colors in the visual spectrum.
It’s why you can shoot white light through a prism and get a rainbow–the prism is more or less just splitting it up for you.
When you perceive color, you’re looking at whatever specific wavelength an object doesn’t absorb. If something absorbs everything, it’s black; if it absorbs nothing, it’s white.
Further Reading: What Is the Blackest Black?
So when you’re dealing with a mirror, it’s whatever color happens to be in front of it. A perfect mirror reflects all colors equally, and thus would be white. Which doesn’t really make sense. Unless you see yourself when you’re looking at a sheet of blank letter paper, which we’re going to guess is not the case.
How Do Mirrors Reflect Things?
Mirrors don’t reflect light in the same way other objects do, though (no kidding). When you’re looking at a pigmented object (let’s say a red apple), it’s absorbing all the colors that aren’t red. At the same time, it’s spitting red back out at you. Thus, you see red.
This type of reflection is called diffuse reflection. The reflected light (in this case, red) goes out in all directions equally. That’s why you can’t see your reflection in an apple or some such.
If non-reflective surfaces reflect one way, a reflective surface is probably going to reflect another way. Which it does. A mirror reflects things specularly, which means the light it spits back out one goes in one direction. Because the light isn’t diffused, you get an image.
This direction is determined by the angle of the incoming light. The reflected light will come out at an equal angle in the opposite direction–which is why you can use a mirror to see around corners.
You can test this angle stuff out yourself, if you’re standing perfectly in front of a mirror, you see yourself. Rotate the mirror a bit. Even though you haven’t moved, the image in the mirror changes based on its position relative to you.
Nothing Is Perfect
You’ve probably been reading this post thinking “alright whatever but nothing is perfect.” You’d be right. Turns out your average bathroom mirror reflects some wavelengths of light better than others. If you want to get into the nitty gritty of how that works, here’s a long paper on it.
That wavelength hovers around 510 nanometers–which to us humans, is green.
You can see what colors mirrors absorb right now. Well. You can if you own two mirrors.
If you place two mirrors in front of each other, they will reflect light between themselves. It’ll bounce back and forth and back and forth, and with each bounce, a small portion of light is lost. Absorbed by the mirror. A white mirror would absorb all these colors equally, but as we’ve just stated, mirror’s reflect green a little better than any other color. That’s why, eventually, you start to see green in the reflections between mirrors.
Like mirrors? Here are a bunch of movies with mirrors in them.