CHROMiX

ColorThink Pro bug?

In the 3D grapher I open an image. I set “Plot as” to Vectors and in “Destination” I choose a printer profile and set the rendering intent to “Abs. Colorimetric”.

Next, I open up the same printer profile as described above in the 3D grapher and notice that the gamut bounderies of both plots do NOT match.

I did the same exercise in ColorThink and the gamut bounderies just match.

See the example below (yellows):
xs4all.nl/~teeuwen/ctp.jpg

Herman

I am not sure what you mean here. If you open an image and plot as vectors, the gamut boundary won’t be shown. What are you matching? Looked at the screen shots, can’t tell what is going on from that either. By the way, you need a printer with a larger gamut :laughing:

–John

If you plot as vectors and set the destination to a printer profile and rendering intent, you’ll see the transformation from image colors to the printer space. In case of the colorimetric intent the out-of-gamut colors are to be mapped along the edge of the printer profile (that is why I opened up the printer profile as a separate plot: a visual aid).

As the upper image (yellows just right of L* axis) will show, the colors lie OUTSIDE the printer’s gamut , instead of along the edge of the printer profile (as ColorThink 2.1.2 shows).

By the way, the printer profile is an Agfa D-lab profile.

Herman

OK, I see what you are saying now. Is this problem specific to this particular profile, or does it happen with other profiles? If only for this specific profile, can you send it to me so I can check it out here?

Thanks.

–John

I gave it a try with a number of other profiles. Same problem !

Herman

In addition:

When testing with other profiles, I found that a specific profile consistently doesn’t plot properly in ColorThink Pro. I opened the same profile in 2.1.2 and it plots OK.

See: xs4all.nl/~teeuwen/procolor_ … _glans.zip

Herman

Yes, I see what you mean. I tried this with a jpeg in sRGB and printer profile Epson 9600 Premium Semi-matte with absolute rendering intent. Some of the colors (notably the yellows) have vectors that end up outside of the printer profile! This doesn’t happen when I use Colorthink 2.2b18.

By the way, is there an easy way to open an image in the 3D grapher and have the number of colors down-sampled to something reasonable? When I open a jpeg that has 68,000 colors in it, makes it pretty tough to tell what is going on.

–John