QTR-Quadtone RIP

Paul & Roy

Many thanks for your assistance.  Very much appreciated!

Fred Drury
Markland Imaging

--- In QuadtoneRIP@yahoogroups.com, "Paul D. DeRocco" <pderocco@i...>
wrote:
> > From: Roy Harrington
> >
> > The nice thing about using Lab is that the ideal values just a
> > straightline.
> > The L values are exactly what QTR linearizes to.  Densities are a
> > more complicated
> > function.
> >
> > If you do want to convert so you can compare dMax etc. these are
> > the formulas:
> >
> > first compute Y = luminance
> > Y = L/903.2               if L < 8
> > Y = ((L+16)/116)^3   if L >=8
> >
> > second compute d = density
> > d = -log(Y)
> >
> > typical whites are around L=95 to L=97
> > typical blacks on matte paper are around L=14 to L=17
> >   on photo paper more like L=4 to L=8
> 
> Or, just go to
> <http://www.brucelindbloom.com/index.html?CompandCalculator.html>
and let
> the machine do it.
> 
> --
> 
> Ciao,               Paul D. DeRocco
> Paul                mailto:pderocco@i...