Digital BW, The Print

Alessandro,

You wrote:

>I must have missed something: where do I get the "color test" curve and
>where exactly do I have to look on the scan from the 21-step scan for the 4
>inks densities?


The list's Files section is at:

http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/files/

The "Color Test" file is in the Message Related Files section, and the
"21-step" test file is in the "Image Procession and Workflows" section.

All the "Color Test" does is pump out 100% of each quad (not hex) ink
separately.  It'll be obvious which ink is which.  The black ink is in the
100% spot (ignore the 90-95% blocks, they are a mix), the cyan is the second
from the left, the magenta (on a quad machine) is the second from the right,
and the toner on the MIS VM or lightest gray (yellow position) Piezo/FS ink
is on the right.

The densities are relevant only when compared to other inksets you print and
measure with your system.  Cross-system comparisons with the tools I use are
too far off to be any more than approximations.  My approach, however, is to
use procedures that nearly everyone can take advantage of without any extra
equipment or software purchases.

Paul
http://www.PaulRoark.com

Alessandro,

You wrote:

>Just to see what happens I opened 21-step image in Photoshop, converted to
>RGB, applied the curve and I measured (with the eyedropper tool) the three
>zones which look cyan, magenta and yellow, and I saw that the values are
>RGB(0,255,255), RGB(255,0,255) and RGB(255,255,0). I must suppose that the
>epson driver consider these values as pure C, M and Y, and therefore
outputs
>a single ink for each of them, am I right?

That is my assumption, and it appears to be close enough to correct to use
the Color Test curve and 21-step test file as a way to compare midtone ink
densities (only the full-strength "colors," not the light/photos inks in a
6-ink printer).
...

Paul
http://www.PaulRoark.com

________________________

-----Original Message-----
From: Paul Roark [mailto:paul.roark@...]
Sent: marted\ufffd 6 novembre 2001 00.20
To: DigitalB&WPrint
Subject: RE: [Digital BW] Quad Ink Densities -- Color Test and 21-step test
file locations

<snip>

All the "Color Test" does is pump out 100% of each quad (not hex) ink
separately.  It'll be obvious which ink is which.  The black ink is in the
100% spot (ignore the 90-95% blocks, they are a mix), the cyan is the second
from the left, the magenta (on a quad machine) is the second from the right,
and the toner on the MIS VM or lightest gray (yellow position) Piezo/FS ink
is on the right.