What type of printer are we talking about here? Are you completely sure it’s not color managed? Is there a RIP involved? Are you sure this is an RGB profiled process? The fact that your AdobeRGB files look over saturaturated could suggest that it is color managed and is assuming sRGB for these files. Either way, I’d send the profiling targets untagged and simply convert images to you custom profile and again send as untagged. Scott Martin www.on-sight.com Imaging Science for Art
On Jul 14, 2021, at 8:45 PM, Miles, Peter via colorsync-users <colorsync-users@lists.apple.com> wrote:
Hi color sync users.
This is a question about my workflow for ‘remote’ profiling a non-colormanaged printer as a ‘back-box’. And if you can see any obvious mistakes in my workflow / thinking.
One of our staff is using an external non-colormanaged print provider. And I'm wanting to help him prepare work for it. Test prints to this printer are in AdobeRGB1998 and prints come out over saturated.
So I am attempting to profile the print process ‘remotely’ using i1 profiler. And to do the color conversion ourselves. I am familiar with profiling inkjet and laser printers where I work using i1Profiler, FieryXF and ColorBurstRIP. I thought it would be a fairly straight forward process, but I’m getting some unexpected results.
I am not in a position to control this external printer in any way. I have already had TC918 RGB patches printed on this printer (patches assigned AdobeRGB1998) and I created a printer RGB ICC profile of this process. When I assign this printer profile to the original AdobeRGB1998 test image we printed I get a very good approximation of the over saturated test print we got. So far so good.
So I Imagined I just needed to use Convert-to-Profile on our AdobeRGB1998 test image, to convert it into the printer color space that I built. Then to ensure it gets handled by the external printer in exactly the same way as before, I just assign it AdobeRGB1998 again.
When I do that, the test image now appears less saturated than it was before. Great, that’s just what I would expect. With the boost of saturation of this print process it should return back to normal when printed.
But what I did not expect was that the blackest pixels in the converted test image that started out as RGB 4,4,9 are now RGB 30,29,28 after conversion. That sounds crazy to me! I have not printed this converted test image yet. I don’t want to waste my money printing this converted file if I have got this wrong. But everything else looks like what I would expect.
Anyone else familiar with profiling printers as a 'Black-box'?, is this kind of thing with the high black point normal?
Thanks Peter Miles _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/scott%40on-sight.com
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