Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Peter Nelson"
<pnweb@s...> wrote:
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Clayton Jones" 
> <cj@c...> wrote:
> > Hello Peter,
> > 
> > >>...in many cases less Dmax. 
> >  
> > >But I don't understand why DMAX should be an issue.
> > 
> > I am referring to the fact (according to Paul Roark) that some 
> systems
> > underlay the black with some other ink, which lessens the Dmax a 
> bit.
> 
> 
> I certainly agree that if it did mix in other colors, even for 
> values at RGB 0,0,0 that it could certainly reduce the dynamic range 
> of the print.   But why would they do that?

It's called a rich black, and it's been done for years for many
reasons. It's usefullness for processes used on this list with
contemporary popular materials is limited. With some ink/paper/drivers
it can enhance dmax, depending on the manner in which it's done. In
other circumstances (ink/paper/driver) it can reduce dmax as has been
noted, but it would be incorrect to say it does as a rule, always.
An example of an inkset that a rich black helped, was the older
Generations color inks with the unenhanced pure pigment K. It was a
lower dmax ink, and leaving the correct amount of CMY underneath helped.
There may be other concerns it's addresses as well, other than just
dmax issues. If I'm using a driver that will allow it, I always test
to see if it can be beneficial.
Tyler