Here is one that I tried: http://dl.dropbox.com/u/15782478/Inkjetmall%20Forum%20Image/iso-gd-cb-955s%20test%20image%20printer%20resolution.jpg
This test file prints out at 4"x6". It seems to yield sufficient detail for relative comparison tests. I compared several prints of this with different platen gap settings on a 3880 and a 7880. The prints show large improvements using the vacuum platen on the 7880 over the 3880… even the finest line widths and lines per inch look great under 8x or 10x magnification on JCS Type 5… virtually no overspray… very clean lines.
If you have any resolution or gradient test images you find useful, please let me know.
I tried this chart on my spanking new R3000 and found that every single line pair, under 10x magnification, was faithfully reproduced. This was true in both ABW and Color modes, using Epson Ultra Premium Presentation paper. In contrast, a print made with the Epson XP400 (a simple office-type machine) showed wiggly lines and color noise between lines.
Thanks for the chart, John.