Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Doug Nielsen" 
<dougnielsen@c...> wrote:
> Roy
> 
> Can you tell me where to find the mathematics underlying the development of the 
table of 
> ideal densities?
> 
> Thanks - Doug Nielsen
> 
> 
> > I don't know if this is really what you want, but I have a table of
> > my "ideal" densities for the 21 steps given a dMax.   It's in my
> > QTR download under CurveDesign, the file is called ideal_density.pdf


The two main references that I've used are:
http://www.brucelindbloom.com/
http://www.easyrgb.com/math.html

There's a ton of stuff on these sites so it takes some exploring.
But the relevant formulas are:

Where L is Lab,  Y is luminance, d is density:
Y = ((L+16)/116)^3
d = -log10(Y)

So if you make the L's linear you get the d's in my table.

Roy