The way the English language works in regards to colors is this: there are the three primary colors (red, yellow, and blue), which each have their own names; there are the three secondary colors (orange, green, and purple) which can be made by an equal mixture of two primary colors; then there are white and black. When you mix one of these base colors with the color right next to it in frequency, or red and purple, the name of the new color is the primary color hyphen secondary color. (So if you mix orange with yellow it's yellow-orange.) When you mix white with any of the basic colors, the name of the new color is "light" name of color--blue plus white equals light blue, for instance. This isn't news to most people.
Some of the mixes have special names--turquoise or teal for blue-green, for instance (not a perfect example because there are two names depending on which of the two mixed colors the color shades toward). White plus black equals grey (or gray). We don't call it "light black" (unless it's much more black than white), but it still is.
So here's the question: when you mix white and red, do you get pink or light red? My answer is both, because they're the same thing. (For the sake of simplicity, I'm ignoring impure pinks like hot pink; it's no more pink than magenta is red. If you consider your basic pink, it's made from red and white. As is light red.) Not everyone agrees with me. My brother, for instance, who in the middle of our discussion of pink or light red appealed to the authority of The Parents, who also think that pink and light red are different colors. Dad's argument was that if I saw something the color of what he was pointing to, would I tell someone that it was pink or light red? Although I have, in the past, answered "light red" just to prove my pink-is-light-red point, the most concise answer was obviously pink. "Light red" is simply not used often enough for the average listener to understand what color was being referred to without pausing to think a second (and even then I'd probably get an answer of "you mean pink?").
What does that point prove?
Nothing.
Well, it does prove that in a case in which two words or phrases could be used to describe the same object, most speakers of English prefer one over the other, but that's not exactly a new observation. In my experience, most people prefer the word "sunrise" to the word "dawn" (except in set phrases like "the crack of dawn") but that doesn't mean that they refer to different phenomena. In fact, an argument based on what one person would be more likely to use when describing something is extremely fallible; if I pointed to an ape and asked somebody to tell me what it was, I'd probably get "monkey" fairly often, even though apes are not in fact monkeys. (File that tidbit of information in the folder marked "it's Istanbul, not Constantinople.") Tap versus faucet. Just because people on this side of the Atlantic might use "faucet" more often than "tap" (except, again, in set phrases like "on tap" or "tap water") doesn't mean that they refer to different objects.
The real test is "if you couldn't use the more common word for something, and you were to indicate that something to someone else, would you use the other term, and would you be understood?" Not in the charades "oh she must be saying bottle because she hasn't been fed for so long" way that barely-verbal children can make themselves understood; no pointing, maybe over the phone. (There's another one; telephone versus phone, T.V. or tube versus television, even wire versus telegram.) If I were to describe my "light red" shirt to my best friend in California, would she know what color I was talking about? If I were to yell to someone in the other room that the tap wasn't working right, would they understand me? Heck, that test even shows that we could get rid of most of our color vocabulary (like that one language, with as small of a vocabulary as possible; it had words for "light/white," "dark/black," "red," "yellow," and "blue," and that was it). Instead of "light green" we could say "light blue-yellow" or "light yellow-blue" and after a moment of thought, most people would understand what color we were referring to.
And my argument (show me something that is "light red" that isn't "pink") fell on deaf ears; frankly, for me, anyone who claims that light red is a different color than pink is, yet can only show me things that are pink, is not all that convincing.
And my final proof: I went to Paint, found the color editor, and started playing around. (If I'd had actual meatworld paint, this would be a better proof, because I'd have my primary colors as my base colors instead of red, green, and blue, but whatever. Go get some watercolors and mix red with white.) To make the perfect color for the base colors, you put it at 255 with the others at zero--"perfect" blue is red-zero, green-zero, blue-255. To lighten it, you pull the little slidey thing on the vertical bar on the right, or you manually change the other two base colors equally (upward)--so that a lighter blue could be 150-150-255. Light green could be 150-255-150. So light red would be 255-150-150. Guess what the color with those numbers looks like?