QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, "Joost Horsten" <j.h.j.h@...> 
wrote:
Last night I thought over my own comments and recalled a discussion 
we had some time ago in the UK print exchange group. I understand a 
bit better now, but still not completely:

> [when using the Gray-RGB-LAB profile] I don't see any difference 
> whatsoever on my monitor with or without softproofing. I also would 
> have difficulty to understand why I would see a difference, since 
if 
> the system is well profiled anything should be linear. The typical 
> use of softproofing as I know it, e.g. checking out-of-gamut 
colours, 
> is not applicable in B&W printing. 

I do think this correct. To my understanding the gray-lab or gray-rgb-
lab profiles should NOT give a difference. If well-profiled, I expect 
the monitor to be linear in the L*a*b* (abbreviated as LAB) space,  
To me, that's the whole point of profiling. Note that the L-values 
run from 0-100 with or without softproofing (at lest when printing a 
standard stepwedge)

> > [...] If you have a 
> measuring
> > device, you can use QTR-Create-ICC to create custom ICC profiles 
for
> > specific ink/paper combinations. These can give very close 
monitor 
> print
> > registration, assuming the rest of your system is calibrated.
> 

This one I understand a bit better now. To my understanding, this 
technique can compensate for two effects: 
1) the tones of paper and ink are in general not neutral 
2) a paper print can not represent the total L-range from 0-100 but 
let's say from 15-95. So the range is compressed, giving this flatter 
look that Tom mentioned. 

Having said this, i'm still not convinced of the use of softproofing. 
The effect 1) is a matter of taste, I use quite heavily blended 
curves (UT3D) , something that can only be poorly represented by 
sooftproofing. Effect 2) is more important, but employing that 
requires (again in my limited understanding) a careful adjustment 
between monitor brightness/contrast and viewing booth setup. Without 
that, my feeling is that softproofing is of little use.

Is this correct or do I still miss the point?

Joost