Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Steve Kale
<stevekale@b...> wrote:
> 
> One other perspective which ought to make you stop and think a
little about
> the current methodology.  Tyler has nicely espoused the current way
of doing
> things:  a desire for a nice linear (straight line) progression of
density
> from dMin to dMax across the full range of pixel values, 0-255 in 8
bit, 0-1
> normalised.  So, for EEM for example, this would mean 0 maps to a
density of
> 1.68 and 1 maps to a density of 0.04 and all other points in between
sit on
> the straight line between the two.  (If I am wrong on this please
correct
> me.)  In so doing you are defining (or calibrating) the colour space
of the
> printer....

Well, if I understand you, not exactly. I've never mentioned a
straight line. I have mentioned calibration to a selectable standard,
a concept about which we have been discussing proper nomenclature.
Roy has selected LAB, IJM has selected user selectable gamma 2.2 or
1.8 (someone correct me if I'm wrong). StudioPrint lets one select any
dot gain along a continuous line from 0 to 49%. I suppose 0% might
bear some relation to "linear", but as you suggest isn't very useful.
I wouldn't call this process having much to do with color spaces as we
think of them, but output density adjustment. Though obviosly the
process "defines" (measures) an uncalbrated output in order to
calibrate it, I wouldn't say we are conciously doing that the way icc
profiling does (accept those profiles made for soft proof, once
linearized). Calibration would be a better term, and if using a RIP
for color, profiling is then done after "calibration".
So again, I suspect we have a linguistics issue.
Also, possibly of interest-
When working with Photoshop gray scale spaces, notice that gamma and
dot gain are interchangeable. So I, for example, could just as easily
work in a 2.2 gamma gray space, and use an equivalent dot gain as my
target calibration in StudioPrint, and achieve the same thing as we
are now doing with a 20%dg space and a 20%dg linearization. Very
similar to Roy developing a LAB based gray space to work well with LAB
calibrated output. We chose 20% because it's a prepress standard and
commonly used.
Have I missed your point?
Tyler