How dark is dark?
Pretty much what you're describing is simple biology. Some of the receptors in your eye do colour, some do black and white. Each type has different brightnesses of light they work best at. The black and white receptors work way way better than the colour ones do in dim light, but in theory you should all still see in colour down to a certain darkness, it just wont be as vivid.
I reckon what the guy may have been hinting at is that some people can see UV light?
There is a certain filter in the eye that, when removed, allows you to see UV. Apparently I think there was some rumour that van gough may have had this filter missing (some people are born without it) and they implied this may well have influenced his work.