Dan Hollick on Making Software: What is a color space?:

In which we answer every question you've ever had about digital color, and some you haven't.

He's not kidding.

Your computer has an operating system, which uses a color space. But your computer also runs applications, which might use a different color space. Those apps can render content, like images and videos, which might be in yet another color space. And then your monitor has its own color space, which might not even match the color space of the operating system. You could even have multiple monitors, each with different color spaces. Yep.

This is a pretty great writeup, and required reading for anyone who deals with color profiles and color spaces. I had only one quibble, and that was the bit which said sRGB was only capable of 8 bits per channel (that's how it's usually used on the web, but you can have 8, 10, 12, 16, 32 bits per channel sRGB images).

Besides being super informative and delightful (I laughed out loud when I saw "A DIAGRAM SHOWING HOW TO CONVERT RGB TO HSL."), the layout of the page is top notch. I'm envious of Hollick's work.