Indeed. If what iSm said were true, then those paint color matching machines at the hardware stores wouldn't work.

Or, more to the point, even if you DO accept the philosophically valid position that color is only perception, it does not therefore follow that black and white is a "truer" state of the world since describing things as black and white still requires accepting 99.999999% of what makes color "only perception" as true. If you aren't acknowledging the perception of color as true, than why are you acknowledging the perception of shape, space, depth, time, matter, opacity, density, etc., etc. as true?

In case anyone cares, the devices are called a spectrophotometer (they are used quite a bit in the printing industry).

If you want, I can bore you silly with discussions on color theory, additive vs. subtractive color, etc. Hey: I took an entire course on this, I have to impress somebody with my knowledge.