In my opinion,
Setting the initial ink restrictions is THE critical aspect of profiling outdoor media.
Unfortunately, this is not an exact science and requires some practice and some degree of 'art'.
I have run initial ink restrictions for SOME colors (particularly C and Y) down in the 40s for some some media, still getting good color, depending on the medias ability to absorb/adsorb ink.
The key to getting good grey balance is to match up the density curves for C and M. i.e. same density, same slope.
In my experience, if the C and M are not balanced up front greys will have a cast. This is not only the density but the curve shape as well. I default to 2 for the nCurves.
If the initial ink restriction choices are not correct, then excessive ink limits have to be imposed, causing clipping and posterization. It just seems as though the icc has to 'work too hard' to try and compensate and gives unpredictable results.
On the EcoUltra ink set we typically set
M very high, sometimes max, but usually in the 80-100% range.
We balance C so that after linerization the C and M curves overlap to look like one curve, so C typically in the 40-80% range.
K we run just a bit higher than the C/M curves, usually near C in the 50-90% range.
Y we tend to run fairly low in the 45-70% range-adding more yellow does not significanly increase Y density but can add a lot of solvent leading to banding/bleeding issues.
The key to solvent printing (even Eco solvent) is the evaporation of solvent. The more ink you put down, the more solvent you have to evaporate. The more solvent you put down the more dot gain comes into play producing banding/bleeding (obviously media dependant).
The balance is between quality and gamut, this is the 'art' aspect of profiling for outdoor media. Variations in temperature, humidity and media all come into play. You can make a very 'narrow' profile with a larger gamut that may work the current environment with the current lot of media, but may not work well as the environment changes or with changes in the media.
