If YourPrinter Manages Color's Prints look more colorful: You are probably right

[Doug Gray]

While I have shown that Perceptual Intent printing with custom profiles only changes the contrast slightly, there is a very big difference in the way the built in drivers print.

So I decided to see how the driver's internal profiles rendered Perceptual.

When a Color Checker image, converted to sRGB (the Cyan is slightly clipped as it is just off the edge of sRGB) is printed on Canon Pro Platinum, 4 of the patches are shifted significantly outside the sRGB gamut.

So Canon is remapping the sRGB images to more saturated colors. Quite a bit more saturated since it knows both the source colorspace (sRGB) and the destination colorspace (printer's pro platinum glossy gamut).


The "Actual" Lab values are all within sRGB (Cyan is on the edge). The measured values are significantly different. The first 3 are about 5 dE76 outside the sRGB gamut and the Cyan is about 14 dE76 out.

[Doug Gray]

One of the advantages of driver embedded color management when the source colorspace, such as sRGB, is known is that colors that are clipped by sRGB but inside a printer's gamut can be expanded to make a print more attractive. There is another side too. About half the problematic colors are not printable but are legal sRGB colors.  These could profit from a gradual compression as the printer's gamut boundary was reached.

I have not tested this but it would not surprise me at all. This is possible with link profiles and special purpose commercial profiles used where the source space is known (and is likely to be sRGB) and could be a great help for folks that just send out their sRGB images for reproduction. It would take care of any gamut clipping that would occur in sRGB due to the sRGB colors that are outside the printer's gamut.

There is some possibility that this is being done now by I1Profiler and ProfileMaker 5. They clip and don't compress printable colors that well outside sRGB but non-printable colors inside sRGB are another matter. It's a reasonable assumption that the source colorspace is not smaller than sRGB and compressing colors there near the gamut boundary could produce less surprise upon printing.

[GWGill]

There is some possibility that this is being done now by I1Profiler and ProfileMaker 5.

ArgyllCMS has supported this since its inception, and was available in the V0.5 2004 release.

[Doug Gray]

ArgyllCMS has supported this since its inception, and was available in the V0.5 2004 release.

Cool. People tend to focus on all those printable colors outside of sRGB. Mapping unprintable sRGB colors smoothly in a printer profile would be both a no-brainer and safe. Pretty good bet people aren't sourcing from a smaller workspace gamut than sRGB.

This I'm going to have to look into.  Thanks.