I, and only I, have the necessary rods and cones in my eyes to determine "pink" from "rose" and "rose pink" from "faded pinkish rose". I can also hear a pin drop at a mile distance. And smell a wild animal over a hundred yards away with the breeze blowing away from me.

The actual truth is some people are pretty good at identifying colors, most likely due to experience, but I'm probably not one of them. But you can see Stallzer's pink stamp above is very definitely as "pink" as you'd ever want a stamp. I'd call it "Girlie Pink" if it wasn't sexist. It's certainly true that our computer monitors are not very reliable with color shades, but many colors do come through fairly clearly and this seems to be one of them. "Rose" seems to have a little more red in it. I used to think "lake" must be a shade of blue -- it stands to reason since it's named after a body of water -- but apparently it's another shade of red. I think all colors have many different shades, blue, green, yellow, and so on all included. Some yellows look orange to me while some oranges just seem really more yellow, and a lot of time color identifications just seem wrong but we're stuck with them, I guess. I even owned a Volvo that I swear to God was green but which my wife insisted was blue. We see colors differently was what I learned from that debate. Hence "teal" was invented, I guess.
But, if you give me an excellent color chart -- and they're all fairly good, I can fairly quickly see color differences. I've been told the Stanley Gibbons color chart one is the best. It's also wildly expensive since apparently making all those color chips perfectly in the correct shades is not easy. Comparing your mystery stamp to a color chart is one way to identify its color.
The best way, though, is to compare it directly to a known color. "Pink" is very distinctive compared to other shades of this stamp. You'll know it when you see it and you'll certainly know it when you put your stamp next to a known pink stamp, and again you can see that with Stallzer's very pink stamp. How you acquire all these stamps in different shades is another issue best solved I suppose by inheriting a lot of money or going to med school.