[argyllcms] Re: Gamut mapping not-monotonic
- From: Vittorio Villani <vittoriovillani@xxxxxxxxxxx>
- To: ArgyllCMS List <argyllcms@xxxxxxxxxxxxx>
- Date: Mon, 6 Dec 2010 10:34:17 +0100
Thanks
I made some print test for the Epson printer. I used Photoshop CS5 with
Relative Colorimetric and BPC.
Prints made with he profile have good colors. I am using a D50 GrafiLite;
monitor profile -i is D65; printer profile -i is D50.
The BW seems to be more problematic.I made some measurement with the ColorMunki
(same hardware used for the profile). I did 3 measurements for each value to be
sure that the reading was correct. I will report the medium value.
For black point (L*a*b* values in the file 0 0 0) I have an a* value of about
-1; L*and b* are close to what I expected (4,2 and -0.2).
For a grey point (L*a*b* values 52 0 0 0 in the file) I have 48.9 -0,8 -0.6.
So what it seems that BW is a little bit green and not neutral.
I made all the reading again using the same targen, printtarg and chartread
parameters (I tought that there could be some bad readings) but I got a very
close profile with the same problems in black neutrality. I used the same
printtarg generated tiff file and the same printed file (printed with AdobeRGB
as file profile and AdobeRGB with RelColorimetrich and without BPC to print
without color management in Photoshop CS5).
My full procedure is this:
targen -v -d2 -fnumberofpatches fileName
printtarg -v -iCM -h -t360 -pBBBxHHH fileName
chartread -v -H -B fileName
colprof -v -qu -i D50 -o 1931_2 -S AdobeRGB1998.icc -cmt -dpp fileName
For this paper (similar to the Epson Premium Luster paper) I made also a 4880
profile witch is more neutral (reading the same patches, using the same file, I
get a* and b* values close to 0 in black and grey). I also used the 7900 with a
custom profile and I get higher L value on the black (5) but neutral a* and b*
(0,2 and 0.1).
Is there anything that you sugges to do to improve the neutrality of the
profile? The strange thing in my opinion is that I have problems only with the
7900; on the 4880 I got better results (and I also a little bit less patches,
1575 vs 1600+).
Vittorio
> Date: Mon, 6 Dec 2010 10:28:58 +1100
> From: graeme@xxxxxxxxxxxxx
> To: argyllcms@xxxxxxxxxxxxx
> Subject: [argyllcms] Re: Gamut mapping not-monotonic
>
> Vittorio Villani wrote:
> > What do you think about this result?
>
> It's more important what you think about the result. You are the one
> with the device, so you only you are in a position to examine the
> results of using the profile. (There is nothing remarkable in
> the verbose output. It all looks typical.)
>
> Graeme Gill.
>
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