Digital BW, The Print

Lab is normally a three channel space: L (luminance), a and b.  Roy has
stripped off the a and b.

With QTR we linearize L values ie we linearize luminance.  Linearize means
you want a nice straight line, ie uniform changes, in L value from dMin to
dMax.  If you have uniform change then you "have good separation" of shades
or grey.  Since we are most concerned with luminance (shades of light
intensity) in B&W and not hue we are focused on L in the Lab space.  (Gray
gamma is RGB but with R=G=B and so one channel.)  We do not need to focus on
a and b at the edit stage.  So nice to have a Lab space without the two
empty channels taking up disk space and memory.  So same as using Lab but
smaller files.


> From: Djon <westsidemaurice@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Fri, 28 Jan 2005 12:33:41 -0000
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: [Digital BW] Re: Gray Lab Working Space and Printing with Perceptual
> 
> 
> 
> Roy, I'm having a ball with QTRgui ...BUT...
> 
> Please explain in simple terms (I'm simple) the meaning and advantage
> of a "pure gray lab working space"
> 
> The beauty of QTRgui seems it's unique ability to let us step away
> from jargon-ridden methodologies, eliminating the necessity for
> profiles... 
> 
> 
>> I have a new download of a pure gray lab working space and printing
>> profiles that take advantage of the color management system.   So there
>> are icc profiles for printing with QTR that do "perceptual intent"
> conversion
>> of your grayscale images.