Datacolor User to User Support Group.

On Sep 10, 2008, at 6:08 AM, rickbehl wrote:

> Hi,
>
> Please could someone help to answer a question.
>
> My setup is:
>
> Screen: Dell LCD 1703FP
> OS: Windows XP
> Screen Calibration: Spyder3 Elite - 2.2/6500k
> Printer: Epson 3800
> Printer Profiling Device: Spyder3 Print
> Paper: Epson Archival Matte Paper
> Inkset: Epson Ultrachrome (standard with this printer)
>
> I have built a printer profile for this printer/paper/ink combination.
> In fact I built 3 profiles:
>
> 1) From the Expert + Grays target (4 sheets altogether) - Take
> measurements after 1 day drying time
> 2) From the Expert + Grays target (4 sheets altogether) - Take
> measurements after 2 days drying time
> 3) Average the two profiles above
>
> On all 3 profiles when I soft proof the image in Photoshop CS3 there
> are a lot of areas showing as gray (Out of Gamut) which do not appear
> as such when I soft proof using the Epson canned profile (Pro38 ARMP).
>
> Noticeably these are in the darker areas: Dark blues, greens,
> blacks/greys, purples, browns. The colours which seem ok (in Gamut)
> are yellows, cyans and generally the lighter shades.
>
> If I print a test image (Using the Photodisc colour test image) using
> the profiles, the colours are definitely better with the Spyder3
> profiles but I am concerned about why there are so many grey/Gamut
> warning areas on the soft-proof...
>
> Please could someone advise ?
>
>

The real issue here is this: the out-of-gamut warning you're getting
with our profile is actually, -technically correct-. Here's why:

You're profiling matte paper. The L values (lightness) for all of the
shadows on matte paper measure lighter than on glossy/luster. On matte
paper, measured L for black will be in the 15-22 range, usually in the
upper teens. On glossy/luster, measured L for black will be in the 3-7
range (but usually not more than 5).

The out-of-gamut warning is telling you that shadow values, with their
darker L's, fall below the measured values for the printer gamut.
(And, in fact: they do!) If you were doing this with a profile built
from glossy/luster with much darker blacks, the gamut warning
would cover a much shallower area of the darkest shadows.

There's nothing "wrong" with this. On matte paper, you simply cannot
prints black, and shadows, that cover the same range as glossy/luster
papers. The gamut warning is telling you this, and there is nothing
you can do... because it's physically impossible for you to print
darker on that printer, on matte paper.

The fact that you're getting gamut warnings in the shadows doesn't
mean that there will be a problem with the print. You will be getting
the darkest blacks and shadows that the printer/paper/inkset can
give you, when you print; the gamut warning is just doing what
it's supposed to do: tell you that you're trying to print darker
blacks and shadows than the printer/paper/inkset can physically
produce.

So: why don't you get a similar gamut warning with Epson profiles...?

You should, but the Epson profiles are doing something different
with an internal table in the profiles (which has to do with how
the gamut warning is calculated) to "hide" the fact that these
shadows are actually outside the printer gamut for matte papers.
The gamut shape in the Epson profiles isn't any larger than
in a profile we've created for the same paper; in fact, our gamut
shape is likely to be a bit larger. If you use a utility like
Chromix ColorThink to compare the gamut shapes for a Spyder3Print
profile on Epson Enhanced Matte, vs. the Epson profile for the same
paper, you'll see that the gamut shapes are similar and that the
bottom tails both "float" above the L = 0 plane at pretty much the
same level.

***

The shorter answer is: don't worry about this. We're actually
giving you a more accurate gamut warning than the Epson profiles;
the fact that those shadows are technically out of gamut doesn't
mean that there's anything wrong with the print. Your direct experience
is that the print is great... and in fact, better than what you
get from the Epson profiles.


David Miller
Senior Software Developer, Digital Color Solutions
Datacolor