Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Ernst Dinkla
<E.Dinkla@c...> wrote:
> Amadou Diallo wrote:
> 
> > With StudioPrint at least, it's a two-step process. To grossly
simplify, the function of 
> > linearization is to map a straight line of input to output
(linear). Following that is a dot 
> > gain adjustment curve setting. This value chosen for this setting
adds a non-linear 
> > gamma-type curve which is better suited to human perception, as we
don't "see" in a 
> > linear fahion.
> > 
> > amadou diallo
> 
> Amadou,
> 
> That extra step is only applied in B&W calibration I guess ?
> 
> Any data available of that gamma curve ?
> 
> When Roy uses Lab's linear greyscale isn't he getting the same 
> necessary deviation from strict linearity ?  A perceptive greyscale.
> 
> Ernst

Ernst, I'm not Amadou but I can reply to that. The last step is in any
mode, including the individual colors for CMYK, overall for quad mode.
It's a dot gain slider. Obviously 0 dot gain is extremely light by
anyone's standard. This entire issue has been a bit of a mystery for a
long time. What is perceptually linear? Is LAB? Probably much closer
than 0 dot gain. What percent dot gain corresponds to linear L values?
I've heard IJC has output gamma setting for the user to select.
Obviously StudioPrint leaves it up to the user to select.
I've put this issue before some pretty extreme geeks, and no
definitive answer came up. LAB has been suggested as a good "probable"
enough times to buy into. But I have yet to correspond a particular
dot gain selection in SP to linear LAB output and I wonder if one
found a setting that gave equivalent 50% density, if they would also
be equivalent throughout the rest of the scale. This is a little
outside my color geek range, so for now I've settled on 20%, and work
in a 20% dot gain space, so far so good. I'm curious what Amadou and
others are using.
Tyler