but none by anyone who does the kind of critical color examination some of our users here can do (and I'm certainly not the one for that; I have trouble spotting crossover even when I know it's there).
Like Donald, I don't have those special eyes that see subtle variations in color and I use digital post processing, so I don't mind pushing the number.
I think that unless you specifically have some sort of color blindness, which I think something like 5 or 10% of males do, you guys can more than likely see fine differences. Offhand, I don't know of a good way to test for it though, without some sort of special test. (We used the Farnsworth-Munsell 100-hue test, I think it was called, which is great for this sort of thing, but costs the better part of a thousand (US) dollars.)
You do need good lighting, too. Here's a little story about that. Someone had asked me to fill in overseeing the end of the 100-hue test on an employee; they're gonna run past the end of the normal workday. So sure, I'm gonna be here late anyway. They finished the test and left while I wrote down the scores. At the end, just for kicks, I thought I'll do the test myself on just one rack of colors. It's just a little game, to see if I can get it perfect. Now I know that if I'm very careful and double check that I can get a perfect score. But otherwise I'm likely to switch a pair of the color caps. (People who are really really good can just go right down the line, bam, bam, bam, and get every one right, no doubt about it.) So I'm going down the line then suddenly run into four or five caps that I CANNOT tell apart. So the first thing I think (knowing that I, visually, have the ability to do this) is OMG, these color caps have faded. That means the test is no longer valid, etc., and all their recent tests are likewise invalid. But then I get an idea; it's still light outside so I open the blinds to let in outdoor light. PRESTO! I can tell the caps apart again.
Skipping most of the details the problem was that the lamps in the office didn't have full-spectral output. (Apparently in the product life of this particular bulb the specs had changed, it becoming a more "eco-friendly" bulb, but keeping the same part #.) Under the deficient light I CAN tell many of the color caps apart, but certain groups look identical to me.
So if you wanna do critical evaluation of color reproduction details in a print, I often suggest to people that they do a "reality check" by viewing with outdoor light.
Another note regarding ability to see fine color differences, on probably dozens of occasions I would hear from IT people in the company, working on certain studio-related projects, the same thing, "I can't tell color apart, the way all 'you guys' can." If we were near a color both with some sort of test going on, I might ask, are you sure? Then I'd lay out a pair of prints - same portrait subjects with slightly different color balance. Fundamentally they look nearly identical. So I might say, look at the skin tones here: does one of the prints seem a little more blue (or whatever it is) than the other? And most of the time they'll point to one - the correct one - and say this one. So I say, see, you CAN tell them apart. So a lot of the time it's simply a case of knowing what to look for, or perhaps HOW to look for it.