[hunter2_]

So is a change of hue required in order to say there's been a change of color? I'm not offering saturation in this question, since "oh that's just a less saturated red" seems similar enough to the notion of "oh that's just a lighter red" that the two ought to be in the same "not color" boat...

[positus]

Assuming the hue and saturation components stay the same, changes in lightness would result in various shades of the same “color”. I think. Maybe. The problem is that in real life changes in lightness result in changes in saturation as well, so things get wonky.

[d1sxeyes]

I think that’s more of a question of semantics than colour theory, but maybe? Is pink just light red? Feels like the answer should be no, and that undermines my basic premise above, so I find myself doing mental gymnastics trying to answer your question, which more often than not is a sure fire way to tell that I’m wrong.