[argyllcms] Re: Absolute colorimetric - dark saturated colours excessively light

Hi Gerhard,

Gerhard Fuernkranz wrote:

Alastair,

I do not understand what you want to "solve"? What you explain, is the expected behaviour. You simply encountered the gamut limitations of your printer on different paper types, and a colorimetric transformation to the printer color space clips colors which are out of gamut on the printer to the gamut boundary. And with the 2nd transformation from printer color space to sRGB, you get a soft proof, i.e. if you would actually print the image after conversion to the printer color space, then the print should look similar to the soft proofs you had posted above. 

Thanks for the response.

I realise that the dark saturated colours are out-of-gamut - but I was a bit startled by how much lighter these patched became.

I was under the impression that the usual gamut-mapping strategy was to sacrifice saturation in order to preserve luminance; the opposite seems to be happening here.

Look at the plain paper version:
http://i14.photobucket.com/albums/a346/robinsonb5/IT8_Plain_Proof.jpg
Device black would be a closer visual match for columns 3 and 4 than what the profile has chosen!

Here's another soft-proof using a profile generated by Profile Prism, using (IIRC) the Tesco paper:
http://i14.photobucket.com/albums/a346/robinsonb5/ProofPrism.jpg

It's not nearly such a good profile overall (because it's made using a scanner, not a colorimeter), but it does better than the Argyll profiles in columns 2-4.

All the best,
--
Alastair M. Robinson

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