Ernst, between you and I, knowing each other on these forums since before most of these people were in diapers, I should stop trying to make sense in these places...
Yes I know, raw RGB equal value data going to the driver for those HPs uses K inks only. My point is since it's never going to be neutral a good profile will convert those image R=G=B values over a bit to make neutral in the print. There still may be R=G=B values going to the driver, but they will be hues in the file that more closely matched that K ink + paper hue.
How much LLK, LK, and K are used in the black channel with Ergosoft are controllable, some experience years back with Colorburst.. looked like LK use could be user set but I don't know it that is still the case. LLK can easily be used up to 0% with both profilers I use. Monaco was a bit more difficult to do that with, the curve tool was clunky, but you could get very close. If I had an HP here to run some test environments on, I could tell you more about ink content up the neutral axis with the RIP. I can tell you that with both an Epson 9900 and a Canon 6300, and controls set for as much GCR as possible from 0 to 100%, Ergosoft uses small amounts of CMY as needed and of course there is a rich black build. Secondary colors like O, G, R, G, B are non-existant up the axis and only kick in as needed to extend gamut. i1Profiler's controls for secondary ink use are extensive but don't work as well as they should, and it's been indicated to me no one cares much...
At any rate, our focus with regard to these issues is very different from that of those who design our tools unfortunately. QTR remains a unique and powerful exception, if only there were HP and Canon support. True B&W looks great, but only for Canon...
The option for Ergosoft niche and finessed B&W setups with OEM inks.. and what may interest you more... perfectly set up ink channels.. particularly K with light ink use perfected for B&W, each channel perfectly linearized.. then dropping image data into apropriate channels in the file (including color channels if you want to tone) results in beautiful work... but much if the labor is done in photoshop. I've even set it up using some of the color channels as spot channels instead of colors... this is pretty off the radar printmaking stuff... color management is involved as well, but in a less conventional manner...
Tyler
The "may not deliver the best print" had the facts you referred to in mind. To sketch the extremes: on a neutral paper with the HP Vivera neutral Ks there is no color at the neutral axis. I am aware that it is more an exception than the rule. In contrast with that is a RIP + profiler that is not using the LLK down to 0%, uses LLK and LK at a minimum, has not only CMY dots but also RGB dots at the neutral axis. Same printer model. So I was curious what your tools allowed.
met vriendelijke groeten, Ernst
Shareware too:
330+ paper white spectral plots:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm