"But with certain vivid blues, turquoises, and yellow greens in certain paintings and in their corresponding ProPhoto files- upon conversion to sRGB, those particular colors are squashed pretty good is the problem.. not a pretty translation and RI doesn't make a difference. The colors look accurate to me on screen in the ProPhoto file comparing with the ptg. "
That's quite interesting, since I could not find anything on the web that addresses the subject of the actual gamut of oil, acrylic, and watercolor directly. I tried every way to ask the search question I could think of and got nothing. Got lots of stuff about paints and painting, but no color space or gamut info specific to art paints. However, on reflection (!) Pointer's Gamut gives us a clue. down the page at
http://dot-color.com/category/color-gamut-standards/ you will see Pointer's Gamut of all reflective colors in nature compared to several device and device independent gamuts. You will see that Pointer is slightly outside argb but well within Pro Photo. Also at TFT Central is
http://www.tftcentral.co.uk/articles/pointers_gamut.htm for more detail. You can check what colors are being squahed using the out of gamut features of Photoshop. It is most likely that RI is doing the squashing.
None of my paintings look like gamut busters. The only painting I can think of that might is Velasquez "Pope Innocent X" with its incredible reds.
