The test you suggest might be interesting, but I can't make it either. Keep in mind that my Macbeth card is 30 plus years old, and hasn't been stored in a way that would make it very close to a current Macbeth card.
But one fast note on your last statement near the end:
Quote:
|
Sample the greys in all photos. Does the average RGB sampling of the Macbeth 18% gray target match that of the Photovision? They are likely to be a bit different. If they are, they're not really both grey -- and then you already own a warmer or cooler "grey" card -- you just didn't know it.
|
They very well may both be gray, just not the same shade of gray. One gray is not warmer than the other or cooler. If something is gray it means that it has equal parts of RGB. So the gray represented by r128,g128,b128 is gray and the gray represented by r64,g64,b64 is also a shade of gray. One is lighter than the other (not cooler or warmer). Cooler or warmer would mean that the rgb values were not equal. So I don't believe you are using these terms in a way that avoids a certain amount of confusion.
Cheers,
rfs