Or ... is it?
When you go to a paint manufacturers website they'll usually list the properties of the watercolors they sell. And one of those properties is how lightfast, or fugitive, or perennial it is. All words that refer to "Does the color fade with exposure?"
There's an official organization that test them. But not everyone uses it and not all colors have been evaluated. And just how much worse is a 1 than a 2 than 3 on their scale?
That's what this is for. A page of swatches of a variety of watercolor paints, ranging from excellent to totally crummy in terms of lightfastness. My plan is to cut it in two, put one half in a drawer and expose the other to sunlight all day long. Day after day. How long do you expect it to be before I see a difference? I have no idea but I'm about to find out!