Digital BW, The Print

> From: David Keenan
>
> After reading here about the long lost Epson ICC profiles for
> matte paper, I tried using one (the 2880 dpi, mk one) and
> printing some 11x17 images that I had been printing using QTR for
> an exhibit that I'm hanging this weekend.
>
> Now, I'm no expert QTR nor digital black and white printer (yet)
> but I'm astonished how much better the ICC prints are. There is
> no comparison in the blackness and depth of the blacks. The ICC
> print leaps out at me compared the flat QTR print.
>
> The blacks in the QTR print have a distinctly grainy look. The
> ICC blacks are tight and solid with no grain. Maybe the 2880 dpi
> setting makes a difference here since I've been using "1440
> super" in QTR.
>
> I know that QTR is very highly thought of so I'm probably not
> doing something as best as it could be done but I'm not sure what
> it could be.
>
> I was the guy who asked about the inherent value of BO printing
> last week.
>
> I also printed the same image using black only using the UC ink.
> (Eboni on the way.)
>
> Another revelation. The ICC print has a distinct green color cast
> to it visible in the midtones that was not so obvious when
> compared to the QTR print but is very obvious compared to the BO print.
>
> I like the ICC print except for the green cast and I'm not
> inclined at this point to fiddle with anything to try to correct
> this. So, the more I look into this the more questions that arise
> but it looks like BO is the way for me to go for my 10 exhibition
> prints -- not what I thought I'd be doing when I started this project.
>
> If any one has any comments on why my QTR blacks might be so weak
> I'd welcome them.

Well, sure. The Epson driver uses a mix of color inks to achieve gray tones,
which means that you get less grain. You also get metamerism (the green cast
under daylight), and faint color shifts at different gray levels. QTR uses
mostly black ink (including light black), and only mixes in the minimum
amount of color inks needed to tweak the tone. The result will always be a
little more grainy because you're trading three dots of each color for one
dot of black. But there won't be any metamerism. (Using 1440dpi may be a
little to blame as well.)

As to the density of the blacks, it's entirely possible that the QTR curve
has room for improvement. But the point of QTR is that you can experiment
and make curves. It's theoretically possible to tell QTR to put out the same
amount and combination of inks that the Epson driver does. Curves are best
built with the aid of a colorimeter, or at least a densitometer, to read the
patches in a test step wedge, but you may be able to coax denser blacks out
of the existing curves by fiddling with them.

If you really want the smoothest tones, with no metamerism, you need to
switch to quadtone or hextone inks, which have multiple densities of gray.
QTR is really designed for these.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...