My comments [GP] interwoven..
[JP] "However, this 'graying' from multiple internal reflections doesn't seem to be what the author was referring to."
[GP] Graying, or loss of chroma, does not come from "multiple internal reflections". It comes from light that reflects from the paper mixing with the light that has been filtered by the ink.
[JP] "The new G7 'how to...' suggests adjusting the gray balance scale, if necessary, to compensate for differences in paper color. (blue white vs. cream white). The basic approach 'automatically' accounts for MIR."
[GP] You can put a curve in a single color (C,M,or Y) to restore gray balance on paper that has a subtle difference in hue from neutrality. Typically this is done to the Y channel if possible since it's hard to see the tone distortion in the Yellow printer.
[JP] "Your gamut plots seem to indicate that, as I suspected, the author is wrong in is assertion...or I am not understanding his point."
[GP] The author's assertion is confusing because it's unclear whether he is comparing different printing gamuts to other printing gamuts or to CRT devices. He says "the nonlinearity of mixing produces a gamut for subtractive reproduction that is wider than would be the case for ideal, non-overlapping pigments." [GP the nonlinearity of mixing does not create a larger gamut] "The gamut of everyday printing inks, and everyday photographic dyes, extends beyond the CRT gamut in certain regions of color space." [GP that's correct, but again not related to nonlinearity]
[JP] "Am I correct in saying that the TOYO ink set is using very clean colors? or perhaps a Rhrodamine red?"
[GP] The use of Rhodamine red would not account for the extra gamut of Toyo Kaleido inks. Using Rhodamine red would just skew the gamut - and you could do this easily your self. ("Magenta" is a powerful gamut swing color. You can use anything from violet to warm red instead to compensate for CMYK gamut deficiencies - but other colors will suffer) This will be the subject of one of my personal blog posts LOL.
[JP] "It seems to me, for example, it makes no sense to have a wider gamut on press, if you compress it in photosphop by using a sRGB color space for the images."
[GP] Hopefully you wouldn't use sRGB for print
[JP] "So, what I'm thinking is that you need to shoot RAW when doing the photography or scan transparencies RGB with with a wide-gamut profile (Don Hutcheson posts one: donRGB.icc)."
[GP] Adobe 1998 is already way larger than TOYO Kaleido - let alone conventional CMYK. I see no reason to use donRGB.
Here's a comparison. Adobe 1998 is translucent - TOYO Kaleido is opaque.
[JP] "On press you would need to use the G7 P2P target with the wide-gamut ink set to calibrate for a balanced gray-scale and correct tone curve."
[GP] You can use whatever technique that achieves the correct gray balance and tonality.
[JP] "The thing I'm a bit unsure of is where to target the SIDs. I hear conflicting advice. TOYO says 20% higher than 'normal' density reading because their inks are more transparent."
[GP] That makes no sense. If their inks are more transparent you will need to run a thicker ink film to achieve the same SID value. Maybe they mean running to a higher SID value?
[JP] "The next step would be to read the IT8 target from the 'characterization' run (after the CtP is calibrated for tone and balance). But, I'm fuzzy as to what do do with this profile."
[GP] I guess you'd create a separation profile to take advantage of the wider gamut.
best, gordo