Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., "Antonis Ricos" 
<antonisphoto@y...> wrote:
> --- In DigitalBlackandWhiteThePrint@y..., chameleon@i... wrote:
> >  Brightness is not the same as 
> > whiteness in paper tech talk.  Whiteness is measured on the "L" 
> > scale 
> > of LAB, whereas brightness is a measure of reflectivity (how much 
> > light is reflected off the paper). 

> But Robert, isn't the L reading the "grayscale" component and not 
> the color? 
> Hence it is expressing the same thing as brightness in different 
> terms (% light 
> reflectance vs position on a grayscale). I would imagine that
> "whiteness" 
> would need to take into account _color_ info not just light-to-
> dark. Color info is 
> only contained in the "a" and "b" of Lab.???
> Antonis

Antonis,
sorry for the delayed response.
you are right that "whiteness" needs to take into account ALL color 
info.  I really should have denoted L, A, and B numbers for the 
various papers i listed.  this is because "color" is a point on the 
grid, and the L reference is not helpful without the other two. i was 
just trying to be quick, but also sloppy.
i'll probably email you a little matrix/excel file that you could 
upload on the files portion of this list for future reference.

However, L is not a function of grayscale. L and Brightness are NOT 
the same thing.  L, with a and b as discussed above, describe the 
color in the 3d grid, whereas brightness is a function of 
reflectivity, and as previously mentioned is dependent on light 
source.

hope this answers your question,
RObert Rex