Digital BW, The Print

Sorry, is this meant to be a subjective empirical test? Ie which do I
subjectively prefer?

I use a workspace of Gray Gamma 2.2.  Someone who knows the intricacies of
this space better than I may correct me, but I would say that if:

Luminance = C * value^gamma + black level

(taken from Norman Koren's site)

And we can usefully set C and black level to 1 and 0 respectively, then a
normalised pixel value will have a luminance of 0.2176. If

Density = - log10(luminance)

Then it will have a density of -0.61.  Given it is a reflected density this
then is 0.61.  That is, to match the workspace I would say it should print
with a density of 0.61.

I thought I had read somewhere that PS uses LAB as the intermediate colour
space when converting from one space to another.  I also thought LAB had a
gamma of 2.2.  Perhaps I am wrong on this.

> From: Paul Roark <paul.roark@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Fri, 3 Dec 2004 08:51:49 -0800
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: RE: [Digital BW] Tonal range and linearization
> 
> 
> Steve,
> 
>> Yes you are right because you in effect manually set the 50% grey slot
>> (presumably with some iteration).  My comment was made in relation to a
>> programme such as QTR where the midpoint is a function of linearization...
> 
> Yes, it is an iterative process.  The driver is a bit of a black box, but
> once one gets used to it, it's quite predictable.
> 
> But, back to the simple question, would L=50 be a better midpoint?  If you
> print a 21-step test strip, like one at
> http://home1.gte.net/res09aij/Test-files.htm, would it match the monitor
> better if the midpoint were more like density 0.73 (a bit lighter than the
> current 60%) than the current 50% = 0.61?
> 
> Paul
> www.PaulRoark.com
> 
> 
> 
> 
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