Digital BW, The Print

Ginny,

Luminance is the tonal value only (or brightness range of the image) 
without the color component.  So, for example, in Photoshop, you could 
duplicate a layer, set that upper layer to a luminance blending mode, 
then play with curves on that layer.  This would change the brightness 
and contrast without affecting the color.  

This is pretty much the same as working on the L* channel in Lab color 
space, where L* defines the tonality of the image, and the a* and b* 
channels contain the color.

Lou

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "ginnylady33" 
<ginnylady33@...> wrote:
>
> 
>   I will reveal my ignorance and ask just what 'Luminosity' is in
> Photoshop?
>  Regards
>   Ginny