You and Will don't understand cause and effect nor proper color management workflows. Let me try once again using photo analogies because I keep hearing I'm wrong because I'm not a professional photographer. Maybe this will make sense to you and Will. The statements below are as factually incorrect about photography, cause and effect for issues (wrong handling of the process) as you propose about the use of Adobe RGB (1998).
Here is what you hoped to say and I hoped you understand.
If you send Adobe RGB to a print path that expects sRGB for conversion to the output color space, you'll get poor results.
Simple as that Will and Gary. Print path means whatever steps, (driver, handling), is used to send the data to the printer. Do you believe that an Epson inkjet is an RGB printer? Despite how all such subtractive printers work and the names of the inks? Guess what happens if you send CMYK data to the Epson driver. You got an ugly (wrong) print because that print path expects RGB data. That doesn't make the Epson an RGB printer nor is any of the devices you used an sRGB printer. You can take the same Epson, place another print path (ImagePrint that Will mentioned and I'm certain is embarrassing the fine people there), you CAN send CMYK data to that Epson. The Epson itself didn't all of a sudden become a CMYK instead of sRGB printer any more than using a different front end with a Frontier allows one to send something other than sRGB previously made it an sRGB printer. There is no such beast.
While awaiting the publication of Mr. Fong’s tests, I decided to conduct my own tests using the Fuji Frontier LP7700 printing on Fuji Crystal Archive paper. As the Digitaldog, Jeff Schewe, and other knowledgeable forum members have pointed out, the test image would have to possess a gamut larger than sRGB for the tests to be meaningful. Otherwise the results would be the same if proper color management is employed. I chose an image of some colorful flowers that was rendered into ProPhotoRGB. The gamut is considerably larger than sRGB and Adobe RGB.
I converted to sRGB, Adobe RGB, and the native space of the printer using the profile downloaded from Drycreek.com. I then uploaded the images to Costco. In one set, I requested that no adjustments be performed; another set was submitted for automatic adjustments. I ordered 4x6 inch prints. The results were indistinguishable between the auto adjusted prints and those with no adjustments.
Here is the image in sRGB for web viewing. There is some blocking up of the yellows in the center of the image and the petals of some of the red flowers on the right, but the image looked reasonably good on my profiled NEC PA241w.
The scanned images of the resulting prints are shown here. The areas where some of the highlights are blocked are circled.
The sRGB and Adobe RGB images are quite vivid, but the highlights in the yellows and reds are blocked up and show no detail. The blocked up highlights or the reds are outlined. As expected, the ProPhotoRGB image is less saturated and appears similar to the image with the Drycreek profile.
Colorthink plots of the image and color spaces helps clarify the situation. The colored solid is the sRGB gamut and the printer profile gamut is in white, but shows color from the overlying sRGB plot with reduced opacity to allow the printer profile plot to show through. The image colors are shown by the dots, and the high illuminance yellows as well as mid-illuminance reds are out of gamut for both spaces. The sRGB gamut is actually larger than that of the printer. Profile inspector shows that the gamut of the printer is 396,814 cubic ΔEs as shown. The sRGB gamut is 832,478. The printer can’t reproduce the high illuminance saturated colors. However, the shapes of the gamuts are different, and some areas of the printer gamut are outside of sRGB and these colors would be clipped when sending sRGB to the printer.
Here is the gamut of the printer:
From this test, I conclude that sending sRGB images to this printer can lead to blocked highlights when the gamut of the image exceeds that of the printer. With most shots, this wouldn’t occur, but occurs frequently when dealing with colorful flowers. In such cased, one should render into ProPhotoRGB and convert to the printer space. Perceptual rendering could be tried (it is not available with sRGB unless one is using the ver 4 profile as Jeff described. Sending a ProPhotoRGB image to the printer actually gives a better result! In this case, the soft proof accurately depicted the image with the printer profile. The colors are more muted, but one could edit the image to increase saturation until the highlights become unacceptably blocked up. In my experience, it is often best to allow some clipping as long as important tonal gradations are not lost.
My conclusions:
• The Frontier is not one of Mr. Fong’s sRGB printers.
• sRGB is not the optimal space in which to send images to this printer.
• One should use the supplied profile and edit with soft proofing to obtain optimal color. ProPhotoRGB is the preferred working space.
Comments on this post are welcome for my benefit and that of others who are not color management experts.
Bill
ps
This post was modified to add a missing image of the scanned photos. 5:00 pm CDT, August 27