Re: [Gimp-user] color proofing / printing -- profiles not applied when printing? gutenprint plugin

[Gary Aitken <gimp dreamchaser org>]

On 01/31/14 05:05, ugajin talktalk net wrote:

> You cannot actively colour manage a workflow unless you have colour calibrated your monitor.

I understand that, and have that on my list of things to get done.

> Also, you do not say if you are printing to Epson Premium Glossy Photo Paper, nor do you say
> what profile/media settings you have selected in the printer driver.

Epson premium glossy paper user, selected in the driver

> The default RGB space has to be something if colour management is active.

true, but not necessarily used.

> However, it is unlikely yourdigital photographs will use this colour space.

As far as my own images go, I'm starting from raw, so the color space is
whatever I export with the image from ufraw.

> ProPhoto RGB, is a wide colour gamut, developed by Kodak.
> It much wider than sRGB and is also sometimes called ROMM RGB.

Didn't realize at first that ROMM RGB was another name for ProPhoto;
found that subsequently, thanks.

What I don't understand is this:
I have physical prints from cone color on Epson premium glossy photo paper,
printed with conecolor k3 inks which were designed specifically to be a 
very close match for epson ultrachrome k3 inks.
Regardless of what the image looks like on screen,
if I import the image and keep its embedded profile,
then print it using the appropriate profile for the printer + paper + ink,
I should get an image that closely matches the professionally supplied
one.
I'm not; it's got too much yellow in the skin tones.

In the gutenprint print dialog, under the "Output" tab, by default it has
the following settings:
  Color Correction:  Default
  Image Type:        Mixed Text and Graphics
I set Image Type to "Photograph", but left Color Correction alone.

If I set Color Correction to "High Accuracy" I see no difference.

Gary

> -----Original Message-----
> From: Gary Aitken <gimp dreamchaser org>
> To: gimp-user-list gnome org <gimp-user-list gnome org>
> Sent: Thu, 30 Jan 2014 21:22
> Subject: [Gimp-user] color proofing / printing -- profiles not applied when printing? gutenprint plugin
>
> Hi all,
>
> I recently installed an epson 3880 and am trying to get decent color out of it.
> I'm relatively new at this and may have more than one thing wrong.
> At the moment I am using the outback photo printer evaluation image as a test,
> since it has rather large color bars and swatches to compare:
>   http://outbackprint.outbackphoto.com/printinginsights/pi049/essay.html
>
> I have my Color Management preferences set as follows:
>   Mode of operation:          Color managed display
>   RGB Profile:                sRGB IEC61966-2.1
>   CMYK profile:               None
>   Monitor profile:            NEW MultiSync LCD 1970NX
>   Display rendering intent:   Perceptual
>   Print simulation profile:   Epson Stylus Pro 3880_3890 PremiumGlossyPhotoPaper
>   Softproof rendering intent: Perceptual
>                               Mark out of gamut colors
>   File Open behaviour:        Ask what to do
>
> The test image has an embedded profile, "ProPhoto RGB", which I chose to keep
> when I loaded it in.  It shows under "Image"/"Image Properties"/"Color Profile"
> as "ProPhoto RGB   Reference Output Medium Metric(ROMM).  I don't know what
> the "Reference Output Medium Metric" means...
>
> With color management disabled in the display filters dialog
>   ("View"/"Display Filters"/"Color Display Filters")
> the image on-screen appears darker and less saturated, with reds too orange
> and blues too violet.
>
> With color management enabled the image looks bright and highly saturated,
> although the saturated green-yellow and green patches become difficult to 
> distinguish.  I suspect that is an out-of-gamut situation, but not sure.
> The photographic images in the test image become much brighter and
> saturated.
>
> If I also enable "Color Proof", things get muted a bit, particularly in the
> test patches, although changes in the actual photographic images on-screen
> are much more subtle.
>
> Questions related to viewing on the display:
> Assuming the incoming image is "correct" with its attached color profile:
>
> 1. Checking only "Color Management"
>      Is this "the best / most accurate we can do on this display"?
> 2. Checking only "Color Proof"
>      What does this represent?  Is it a rendering of the image mapped to
>      RGB and then color-corrected for the printer, and therefore incorrect?
>      Is any display color-correction included in this?
> 3. Checking both "Color Management" and "Color Proof"
>      Is this the proper way to preview an image for printing?
> 4. This dialog is labelled "Display Filters".  I am assuming that means
>    items selected here *only* affect how the display appears, and has 
>    nothing to do with printing.  Correct?
>
> The images being printed appear similar to what I see on the screen with
> "Color Management" unchecked, and "Color Proof" unchecked:
>   When printed, the most saturated reds appear dull and orangeish
>   The image has three saturated greens, clearly distinguished in unmanaged
>   mode on-screen, but with two of them difficult to distinguish in managed 
>   mode on-screen.  The prints have the clearly distinguishable green
>   pattern seen in the unmanaged image on-screen.
>   In unmanaged mode on-screen, the blues tend towards violet, which is
>   what they do when printed.
>   CMY are all less saturated unmanaged on-screen, and printed.
>
> In the gutenprint plugin, the printer command being issued is
>   lp -s -d 'Epson_Stylus_Pro_3880' -oraw
>
> I also have the test image from Cone Color
>   http://shopping.netsuite.com/c.362672/site/test-image.zip
> and the two test prints they supply which are supposed to be color-corrected
> and should match epson inks very closely.
> If I use the Cone Color test image and compare the output to the sample 
> cone-color k3 ink sample, there is clearly too much yellow in the skin-tones.
>
> Any help / hints would be greatly appreciated.
>
> Thanks,
>
> Gary
>   
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