Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., "Nij" <nigel@m...> wrote:
> Martin,
> 
> Answered interspersed with your text...

Ditto.
> 
(snip)
> >
> > Also if you run all four inks into the black area I would expect a
> > lighter result since you are diluting the pure black with lighter
> > shades or because the lighter inks wind up on top of the darker 
ones.
> > What I saw on the squares looked like a dusting of lighter ink on 
top
> > of the black ink.
> 
> I would have thought the opposite! I can see that you did test 
this, and
> have seen it to be the case... but I would have thought that 
diluted pigment
> on top of pigment would end up as being pigment on pigment (once 
the carrier
> had dried off) - ie the equivalent of printing the sheet twice as 
has been
> discussed recently. Perhaps, though, what you see is the small dye 
component
> of the ink. Intriguing.

My thoughts follow yours and if the inks were just dilutions of the 
same black base you should get an additive result. So either there 
are some lighter pigments in the other inks or we are seeing a 
situation where the ink is perhaps laid down or dries differently 
resulting in a more matte finish. In any case maybe Jon can take a 
look at this in the next generation of inks.
> 
> > This is very easy to do and you can see for yourself.
> >
> > In any case, it does suggest that it might be possible to adjust 
the
> > Piezo driver to deliver just the black ink at the 100% level to
> > increase the Dmax slightly. I don't think we are talking about a 
big
> > difference here and there may be other tonal trade offs which are
> > less desirable.
> 
> Have you tried the gamma settings in the driver? I have not... so 
can not
> advise on the results.

I have played with the gamma settings once trying to create a profile 
for the Eclipse Satine paper. I used the "Unsupported" profile and 
set the Gamma to about .93 and the Dot Density to 104%. These small 
changes in value have huge changes in the print. For this paper I 
need more of both to build the blacks but was already pushing into a 
posterizing situation so the paper needs some sort of additional 
curve.

My impression is that the Dot Density increases ink loading and Dmax 
and the Gamma moves the midtones around.

Martin