I wanted to test one of Doug Gray’s Packed Patch Sets relative to the X-Rite 2371 Patch Set I have been using for making profiles, following information from Ethan Hansen about which numbers of patches are optimal for building targets to use with i1Profiler. The printer and paper are an Epson SC-P5000 with Ilford Gold Fibre Silk paper. I asked Doug which of his packed sets he thought would be the best to use for this purpose and he recommended the N=10 file (1734 patches). So I created the targets from his *txt file in 1lProfiler, saved the target sheets as TIFF images, opened them in Adobe Color Print Utility and printed them using the same Media Type that I had used for the 2371 patch target (Epson Legacy Baryta). After letting the target prints dry over night, I created a profile with them and printed two verification targets with Absolute Rendering Intent: (1) my usual 24-patch (very slightly) modified GMCC , and (2) a 48 patch target I recently configured that has a good range of in-gamut RGB and CMYK colours and in particular more neutrals (to be described in detail and open for discussion in another context at a later date). I let the targets dry over night and then measured them, moved the measurements into my Excel analytic templates and examined them.
This post describes the comparative results for the two profiles (DGN10 vs XRite 2371), both for dE 76 and dE2000 and these four results for the 24 and 48 patch sets, making for a total of 8 comparisons, showing for each Average dE and its Standard Deviation (St. Dev). Hence, total 16 observations. To recall: the lower the dE and the lower the St. Dev, the more desirable the outcome. I also provide insight into Black and White tonality and neutrality.
Firstly, looking at the profile itself, the gamut volume is outstanding, at 997,526. This is the highest gamut volume I have seen with any printer/paper profile I’ve measured or created. I’ve come close with the XRite 2371 target at about 987,000 for the same printer/paper, so pretty close, but Doug’s N10 beats it by a tad. The profile shape is also very satisfactory (Figure 0, 2D representation).
Secondly, the comparative results (Figure 1):No complaints for any of it. For the most part, within each of the dE metrics, differences are on the whole quite trivial. Between dE76 and dE2000, all the dE 2000 results are lower than their comparative dE 76 results. This is normal and expected. I'll let the numbers speak for themselves.
Figures 2 and 3 show the results for the 14 neutral patches of the 48 patch set. I know the file values of these patches are completely neutral because I constructed them that way. Likewise I know the Luminance values in the target file are accurate as intended. The two questions answered in these graphs are (1) How close are the printed Luminance (L*) values to the file Luminance values, and (2) how neutral are they (or do they print with any hue bias, be it Lab a* or b* different from zero)? In the upper portion of the graph, the closer the red line (printed values) adheres to the black line (file values), the closer the Luminance values read from the print cohere with their file reference values. As you can see, the lines are almost convergent for both profiles. In the lower portion of the graphs, the closer the bars to zero (hugging the X axis), the less the hue bias. As you can see, all of them are well below 1 Lab value above or below zero, so much so, that taken together no one pair of a*,b* outcomes will likely be perceptible as non-neutral (this graph is not a dE calculation but shows the ingredients thereof - it is meant to indicate basic arithmetic departures from neutral).
