I guess you're asking me amongst others...
I use Ergosoft PosterPrint.
Does this differ much from StudioPrint (also by Ergosoft)? How many individual colours (not including light/diluted versions) does it support? Does it support variable drop size?
Dot gain and absorbancy are dealt with the normal ways.. with light ink limiting, individual channel linearization and limiting.
Apart from pure carbon inks (which are completely stable regardless of dilution), I'd prefer to avoid light ink wherever possible, due to the reduced lightfastness of diluted inks. Better to use smaller dots of full-concentration inks, rather than diluted inks. If only the standard Epson heads went down to 1.5 picolitres, using a combination of 3pL and 1.5pL dots for the highest print quality... How much would removing all the light inks cost me, gamut-wise? Could this be made up for by introducing more dilutions of black ink (up to 7, as with Cone inks) or by using more inks of nonstandard colours? Just as importantly, would your RIP program be able to handle an inkset which included red, green, orange, brown and other ink colours, in addition to the standard CMYK?
Total ink limiting, K generation, O & G generation, these things also effect those issues and are done in the profiling after the other issues are controlled.
Shouldn't K generation, as well as orange/green and other colours, be done in the RIP, controlling individual inks, rather than in the ICC printer profile?
Ideally, for Lab values equalling those produced by the pure carbon pigments on paper, you'd want to set it so that the only inks used to generate those colours were the carbon pigments, with no coloured inks at all. You couldn't do this in the ICC profile. Same with black-and-white RIPs - you'd set it so that only the pure carbon inks were used, or with small amounts of coloured inks for toning.
Linearising a specific ink colour is easy enough - it's just a matter of measuring density and Lab values along a gradient of that particular ink colour. The hard part is getting all the various coloured inks to work together - particularly if there are nonstandard inks like red, green or brown - to produce whatever RGB values are forwarded to the RIP via the printer profile. How good is Posterprint for this sort of thing?
Rebalance? Again, that would be taken care of in profiling, over a well linearized and limited paper setup. Dot settings are all totally controllable and also play a role to help minimize mottle and bleed on those kids of papers.
In other words, using the RIP , and an ICC profile to convert the file's Adobe RGB colour space into the equivalent RGB values for the printer's colour space, which the RIP can then use to determine the exact mixture of inks needed to replicate that particular colour?
No, densities and gamut on Arches, no matter how carefully set up, will not exceed the good coated fine art papers, nor will resolution.
I once saw a recorded Dmax of 1.7 on Arches Hot Press. This was with preheated inks and paper on a solvent printer, using a single-pass technique (multiple passes could achieve a deeper Dmax, but would add further problems with registration and profiling).
I wonder if replacing the solution in which the pigment particles are suspended with an alcohol-based, rather than water-based solution (still aqueous, since ethanol is water soluble) would improve things, since alcohol's faster evaporation would reduce dot gain and increase possible ink load. Keeping the pigment from settling would be a challenge, though.
Getting into more detail about all of this is more like a PosterPrint tutorial and very very few will be interested...
I guess that's why it's an individual thread on a very specialised subforum on a website that is itself specialised!