Digital BW, The Print

Cleavis,

>[Is] there a reliable relationship between the
>info box (Photoshop) and the output tone once the curve is applied?

>If you have a K only sampler, will that indicate a percentage tone
>laid down by the ink?

I hope so.

The simple answer is that when the eyedropper in Photoshop reads a patch as
0% -- pure white -- the printer is supposed to put zero ink there, and if
the eyedropper reads a patch as "100%" -- "pure black" -- the printer should
be laying down as much black ink as possible.

However, there is a question as to how one measures the print densities and
what a "linear" output should be.  That is, between those obvious end
points, what should the "gamma" or slope of the curve be?  How dense should
the 50% patch should be?

If you print the grayscale ramp with many printers, the 50% patch might be
lighter or darker than the 50% patch that results from one of the vm curves
or from the Piezo driver.  And, what the "50%" patch on a test strip will
read on a desktop scanner is a function of how the scanner gamma is set.

I called Epson to see if there was any way to get my scanner to be "linear."
There isn't.  They don't claim that any particular setting will give any
particular slope to the curve.  It's all just relative.

The densitometers are a more reliable way to see what the densities are.
The average 50% patch on the old PiezoBW test strips I've made and seen is
about 0.61 - 0.62, and 0.61 is what I use for the vm curves.  This is
clearly not half way between the paper white -- about 0.04 -- and the VM-K
100% patch density of about 1.65 (depending on printer and paper type
setting).

So, the only simple answer relates to the end points.  After that, one has
an open question as to what the "50%" patch should read.  The three test
strips that are in my fader had 50% patch readings as follows: 2200 - 0.57,
MIS Archival color - 0.60, and PiezoTone-S - 0.69.

Paul
http://www.PaulRoark.com