My ex-husband and I used to have a running argument about colors.
Before you say “no wonder you got divorced—what an asinine thing to argue about!”—let me just say that it wasn’t a hostile battle. It was a mild, intermittent, slightly silly, tongue-in-cheek-but-a-bit-serious-as-well disagreement about blue vs. green.
We agreed on some things. For example, this was undoubtedly green:

And this was blue as blue could be:

Ah, but those gradations and shades in between! Where oh where to draw the line?
The distinctions between colors are not arbitrary, but neither are they exact. And since the names of colors also are not infinite, we have to make decisions about categories of color and where they end.
When does green segue into blue, and back again? One individual can choose a different point than another—as can entire cultures and people in different language groups.
My ex-husband and I were from the same culture, but he was a man and I a woman (still are, in fact). Did that matter? Men are more likely to be color-blind, but that was not the case with my ex-husband. He could see colors well enough, as could I. Our differences had to do with naming them.
If you think that the naming of colors is a simple thing, you would think wrong. Think about those endless paint sample cards in the hardware store, and all those fine gradations between hues, and then think of the people who have jobs coming up with names like “Amazon Moss” and “Champion Cobalt”
Wiki lets us know how different cultures see it:
Different cultures have different terms for colors, and may also assign some color terms to slightly different parts of the human color space: for instance, the Chinese character é’ (rendered as qÄ«ng in Mandarin and ao in Japanese) has a meaning that covers both blue and green; blue and green are traditionally considered shades of “é’.” In more contemporary terms, they are è— (lé¡n, in Mandarin) and ç¶ (lÇœ, in Mandarin) respectively. Japanese also has two terms that refer specifically to the color green, ç¶ (midori which is derived from the classical Japanese descriptive verb midoru ‘to be in leaf, to flourish’ in reference to trees) and グリーン (guriin, which is derived from the English word ‘green’). However, in Japan, although the traffic lights have the same colored lights that other countries have, the green light is called using the same word for blue, “aoi”, because green is considered a shade of aoi, similarly green variants of certain fruits and vegetable such as green apples, green shiso (as opposed to red apples and red shiso) will be described with the word “aoi”.
Lest you think these strange distinctions are an Asian thing, remember that English has its oddities as well; we just don’t think of them as odd at all:
Similarly, languages are selective when deciding which hues are split into different colors on the basis of how light or dark they are. English splits some hues into several distinct colors according to lightness: such as red and pink or orange and brown. To English speakers, these pairs of colors, which are objectively no more different from one another than light green and dark green, are conceived of as belonging to different categories. A Russian will make the same red-pink and orange-brown distinctions, but will also make a further distinction between sinii and goluboi, which English speakers would simply call dark and light blue. To Russian speakers, sinii and goluboi are as separate as red and pink or orange and brown.
I never thought of pink as light red. But of course it is.