To answer Mark's question regarding Color Rate RIP - Tone Value/Density.
The HP paper profiles are used by Colorgate for media description/control only. So star wheel position, feed, paper thickness. These are things that Colorgate cannot control. As far as I know, the amount of ink is overwritten by Colorgate's own profiles/linearizations. It makes no difference at all whether you use Pearl more ink or Pearl less ink, the Colorgate profile determines the amount. They also have a technology called "save ink" that can save up to 30% ink with supposedly the same visual results. I haven't licensed it, but it is offered for the HPz9 + - but the point is, that only works if you can control the amount of ink. Colorgate works internally completely in CMYK + other inks, but if you operate a supported printer in RGB mode they implement the changes internally. The standard max. value for the amount of ink is 400% (C=100%, Y=100%, M=100%, K=100%).
There are a few possibilities to control the amount of ink indirectly/directly, both when profiling and when printing in RGB mode.
When profiling:Pure Black:
The Pure Black option e.g. avoids the creation of a four color black (CMYK) for pure black RGB text and uses only pure black for printing. This option converts an RGB input value of 0/0/0 to a pure printing black, i.e. 98%.
Pure Gray:
Using the Pure Gray option, the gray balance in a CMYK printer profile is composed by black ink only. However, this only makes sense if your printing system has a very neutral black, from the highlights to the shadows.
In RGB printer profiles, the effect of Pure Gray is that the gray balance is composed of equal amounts of RGB values. This proves to be a very useful option in the case of RGB-controlled ink systems, for example.
GCR
(Gray Component Replacement), proportions of CMY in all image areas are replaced by black color. The reduced ink laydown and the shorter drying time are particularly useful for uncoated papers. Unlike reprography, modern color management always preserves a little magenta at max. GCR. (Gray Component Replacement): Portions of CMY in the any image areas are replaced with black color. GCR replaces the primary colors cyan, magenta and yellow in the colored and neutral parts, until one of the primary colors disappears, with black ink. It improves the saturated, dark colors more than UCR. The neutral, gray parts are almost completely created with black ink, so the gray balance will become more stable.
GCRSmooth: Same as GCR but with optimizations to get smoother gradients.
You can look at the profile's Tone Value Index.
The gray balance
While printing:With Colorgate, the profile and the linearization can be managed separately. This has the advantage that you can make several live derivations from one profile. Of course, you can also classically create several different profiles for one paper.
You can influence the tone value index. For all channels or individually.
The grayscale conversion and tint
You can influence the gradation. For all channels or individually.
The Tone Value Index Print module should come closest to the slide rule for the amount of ink. You can only fully influence it with a real CMYK printer or various Epson/Canon printers that have an HTM / NON-HTM module (half-tone-mode). In addition to CMYK, you can also define all other inks such as Lg (light gray), lc (light cyan) orange etc .. and fully control. Unfortunately the HPZ9 cannot use the HP Contone mode.
But you can definitely overcome one hurdle with Colorgate. If you are profiling a paper from HP that has the "only low ink mode" permanently set, but you want more ink. Colorgate overwrites this and controls it using the profile created in Colorgate or the other options listed above. This works in any case, even if you cannot control it as granularly as you might want.
Greetings Gerd