A profile is meant to be a model of the device (i.e. printer) behavior. ….if it were me, I'd simply drill down. Figure out the L*a*b* of the problem color. Look that up in the profile to get the device values. Print test patches of that device color and measure them. Do the forward lookup of that device color and check the L*a*b*. Lookup that L*a*b*'s device value in the source profile. Convert that through the linked source and destination profile and check the resulting printer device value. etc.
If anyone is still interested in this, here’s an update: We still have not found any reason for or solution to the anemic reds that we’ve been getting in prints from our 4900 and the more we look into this, the stranger the issue becomes. We’ve encountered some interesting test results as we've explored this.
To review, the printer is an Epson Stylus Pro 4900. All nozzles are completely clear. The Vivid Magenta and Vivid Light Magenta inks are new. They were replaced when the issue first became apparent. The paper is Ultra Premium Presentation Matte from Epson. But, as it turns out, other papers are also affected. The custom profile we used had been created two years ago. But, it had worked well until early February when things suddenly changed i.e. reds were suddenly very weak - anemic. The image currently in question is a scan of a painting of a woman’s face in cameo which is primarily comprised of skin tones and warm copper tones. The image was painted on an 8" x 10" copper plate.
We made and printed through 2 new profiles which did not solve or even change the issue. ColorThink Pro revealed that the second profile also turned out to have some malformations as it had been hastily made. So, this week, to really drill down on this thing we made a new profile from 2 sets of large targets each of which was scanned twice through our Isis-2. This yielded four large sets of data which was averaged and two profiles were generated one for M2 and the other for M1 conditions. The structure of the new profiles is much smoother and more uniform than the previous profiles, as seen in CTP.
Then, for our first test, we imported the image into ColorThink Pro, selected 100 colours from the image and transformed them through the UPPM M2 profile. CTP reported average Delta-e2000 of 0.93 to 1.73
For comparison and context, the same colours were transformed through a 1 year old Hot Press Bright M2 profile from the same printer. CTP reported Delta-e2000 average of 1.03 to a high blip of 2.15. A soft proof through this profile looked very good. But a print through that profile on the Hot Press bright yielded a print which was as anemic as the other prints on UPPM.
The soft proof of the file in PhotoShop through the UPPM profile looks good as well i.e. no indication of anemic reds. That said, it had also looked good though the old profile, despite some anomalies in the profile and the anemic result in print. Again, out of interest, we soft proofed through our Hot Press Bright profile as well as the UPPM profile. A comparison of the 2 soft proofed images revealed no appreciable visual difference or change as far as the copper tones and reds are concerned and both soft proofs looked very good.
Nevertheless, the actual print from the 4900 on UPPM is as anemic as before - consistently so. The overall appearance has moved from the warm copper tones in the image to cool sandy browns in print. In fact, there is no immediately apparent difference between the printed result from new profile and previous prints through the old profiles.
Then, we printed the same image on a P5000 which sits a few feet away from the 4900. But we used the same profile from the 4900 for the UPPM stock. To our amazement, the print was very close to the original image - the copper tone reds were all ok.
Following that we ran another print back on the 4900 through Photoshop using “Printer Manages Colour" and "Adobe RGB.” The print was good
! No trouble at all with the reds.
BUT then we ran another print on the 4900 this time through Epson’s canned profile for that paper and the result was as anemic as the prints through our own profiles. They were all very close.
So, in conclusion, the new profile appears to be ok when printed by the P5000 on UPPM. And the Isis2 appears to be working well especially in view of the fact that we have recently made many new profiles for our new P9570 which are performing beautifully. Finally, it appears that the 4900 is still capable of printing the reds properly but not through ICC profiles - custom or canned.
So, my question is what the hell is going on here? Has anyone experienced this sort of thing before?
Thanks for your time,
Mick