Profiling issues

[Palindrom]

Hello,

When building an ICC profile for my Epson Stylus Photo R800, I run into couple of issues (driver version is 2.16.2 registered).

1. Ink limit

When creating a new profile and printing ink limit test on the printer which has the CMYKRB ink set, I noticed that only the saturated green patches are bleeding with the default limit of 250 (the reason seems to be obvious, as saturated red/blue patches use single ink). Nevertheless, I have to set the overall ink limit to 175 (for the Epson Premium Glossy paper) to avoid that.

I suspect that setting this limit causes the weird "dips" on the gamut:

r800-1.png (76.2 KiB) Viewed 1009 times

Could you please advice if there is a way to limit C+Y for the saturated green only without affecting the other colors, e.g. using the separate C/M/Y ink limit controls on the "Ink Ctrl" tab?

2. Gray balance/neutrality

When building the profile, I discovered that grays are far from the neutral axis:

r800-2.png (116.53 KiB) Viewed 1009 times

So, I have to take special measures when generating a test chart to avoid the rather strong cyan cast on the prints. Is it normal for the TP driver? If not, where may the problem be?

Thanks in advance.

--
Regards,
Alex.

[zedonet]

Hello,

thank you for your very descriptive explanation.

1. "Dips" in profile:

Ink limit should be 200% or more, otherwise there can be "dips" in color gamut.

If you are profiling a glossy paper, you could choose "Type of paper"="Other" instead of "Glossy". This setting is just like "Glossy Paper" but with less ink applied for paper that accepts less ink. Another possibility is to create the profile with "bleeding" green patches (if it is possible to do the measurement) and limit ink application later when printing.

2. Neutral grey

The R800 printer has been linearized with an EyeOne spectrometer using the "Density" reading on Epson Inkjet Paper (for the setting "Type of paper="Matte Paper") and on Epson Premium Glossy (for the setting "Glossy Paper"). This produces almost neutral grey, the remaining color cast is removed by the color profile.

If you are using a different paper or different inks, there might be a stronger color cast.
For better results, a new linearization would be necessary - this is especially necessary if non-Epson ink is used.

Could you please post the following information (this might help to find a solution on how to create a better profile):

- paper type / manufacturer
- ink
- other settings in the profile creation dialog (Paper Type, Print Quality, Gloss Optimizer)?
- spectrometer / measurement device
- profiling software

[Palindrom]

Hi,

1. I printed the ink limit pattern on Epson Premium Glossy with the paper type set to "Other" as you suggested. The maximum value is 250 in this case. I'm going to proceed profiling with these settings. With limits 275 and 300, only the very dark patch in row 6, column 3 bleeds (I'm unable to identify its color). Thanks for your advice!

2.
Paper: Epson Premium Glossy
Ink: Epson Ultra Chrome Hi-Gloss

The supplies have been bought from an official reseller.

Settings:

• GlossOpt: auto
• Quality: Photo 5760dpi
• Paper class: glossy
• Ink limit: 175
• Color -> Intent:
  
  • No correction -- when printing chart
  • Perception -- when completed
• Color Space: BestRGB

All the other settings are default. The chart was printed with the paper set to the name of a new (incomplete) profile.

Spectrometer: ColorMunki Photo

Software: Argyll CMS, v.1.3.2 (latest)

Workflow (if it helps):

targen -v1 -d2 -f630 -G -e6 -s21 -g41 chart#630
printtarg -iCM -p A4 -h chart#630
chartread -v -H -B chart#630
colprof -v -qh -cmd -dpp -S BestRGB.icm -O R800-TupboPrint-EPG-175-LABLUT#630-HQ-R1.icc chart#630

Please let me know if you need more info, including any Argyll's intermediate files and the ICC file.

Thanks and regards,
Alex.

[zedonet]

Thank you for the information!

If you are using Epson ink & paper, gray linearity (before profiling) is already "as good as it can get".

The deviation is only with darker colors where black ink is being added (brighter grays are mixed from CMY inks only). I'll have to look at the driver if something can be fine tuned / improved. Creating a CMYK profile might also improve quality.

Do you get neutral grays after profiling?

[Palindrom]

Hello,

I've built another profile with the ink limit 250 and the paper set to "Other":

gamut.png (125.88 KiB) Viewed 976 times

As may be seen, the dips disappeared but the grays are still far from the neutral axis...

Before profiling, I've replaced cyan, magenta, matte black and gloss cartridges and started a new box of paper.

Regards,
Alex.