Assessing color reproduction tolerances in commercial print workflow

Assessing color reproduction tolerances in commercial print workﬂow G. Beretta1 E. Hoarau1 S. Kothari1 I-J. Lin2 J. Zeng1 1 Hewlett-Packard Laboratories, 1501 Page Mill Rd., Palo Alto, California 2 MulticoreWare Inc., 1375 S. DeAnza Blvd., Cupertino, California Color Imaging XVII: Displaying, Processing, Hardcopy, and Applications San Francisco Airport, 24 – 26 January 2012Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 1 / 12

The nightmare of ICC profiles the ICC profile standard has no provisions for workflow oftentimes embedded profiles are incorrect oftentimes profiles are of poor quality workflow system must be able to swap out profiles want to target good enough quality for given price point (SLA) select relevant papers: Lammens, “Night of the living color: horror scenarios in color management land,” this conference 1998 Phillips et al., “Comparing image quality of print-on-demand books and photobooks from web-based vendors,” JEI 2010 Beretta et al., “ICC profiles: are we better off without them?” this conference 2011 Falkenstern et al., “Adaptively selecting a printer color workflow,” NIP 2011 Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 2 / 12

Assessing print quality average ∆E values are not useful a useful metric must allow speciﬁc assessment Peter Zolliker et al. from EMPA have proposed several more useful methods is there a simpler method? Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 3 / 12

Color fidelity vs. color integrity in practice, color fidelity is not that critical Phillips et al., “Comparing image quality of print-on-demand books and photobooks from web-based vendors,” JEI 2010 print does not contain sets of unrelated colors but color palettes goal: preserve the integrity of color palettesExample (catalog selling denim garments)One page might have jeans in original, washed, and stone-washed denim,while a second page might have corresponding jackets. The specific hue ofeach garment is less important than being able to match jackets to jeans whilepreserving the rank of the processes Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 4 / 12

Farnsworth-Munsell 100-hue test in the case of humans, color discrimination can be assessed with the Farnsworth-Munsell 100-hue test can we use this test for color reproduction systems? Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 5 / 12

Scoring transpositions Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 6 / 12

Graphical evaluation 2 1 85 84 83 2 1 85 84 83 4 3 82 4 3 82 5 81 5 81 6 80 6 80 7 13 79 7 13 79 8 8 9 12 78 9 12 78 10 77 10 77 11 11 11 76 11 76 10 10 12 75 12 75 9 9 13 13 8 74 8 74 14 14 7 73 7 73 15 15 6 72 6 72 16 16 5 5 17 71 17 71 4 4 18 3 70 18 3 70 19 69 19 69 R R 20 YR RP 20 YR RP 68 6821 21 P 67 P 67 Y Y22 22 66 6623 23 65 65 GY PB GY PB24 24 64 6425 25 G B G B 63 63 26 BG 26 BG 62 62 27 27 28 61 28 61 29 60 29 60 30 59 30 59 31 58 31 58 32 57 32 57 33 33 56 56 34 34 55 55 35 35 36 54 36 54 37 53 37 53 38 52 38 52 39 51 39 51 40 50 40 50 41 42 49 41 42 49 43 44 45 46 47 48 43 44 45 46 47 48 Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 7 / 12

Practical application FM-100 assesses entire hue circle we need to assess only the critical color ranges include one or more scales in the crop margin normalize scores to FM-100 examples of parameters to assess: ICC proﬁle plausibility & correctness ICC proﬁle reputation & precision rendering intent gamut mapping algorithm black skeleton halftoning inks, process vs. Hexachrome; spot colors media Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 8 / 12

ExampleA uniform color scale in CIELAB from (80, 15, 2) to (85, 20, 45) 86 40 84 L* b* 82 20 80 14 16 18 20 0 14 16 18 20 a* a*The non-uniformities are due to rounding the coordinates to one decimal digit Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 9 / 12

Reproduction on ofﬁce laser printer 88 40 84 L* b* 20 80 76 0 14 16 18 20 14 16 18 20 a* a*∆E94 = 5.6 Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 10 / 12

Comparison of 3 devices 24 84 22 40 L* device a* device b* device 20 80 20 18 76 16 0 76 80 84 16 18 20 22 24 0 20 40 L* a* b*∆E94 : green device: 5.6 red device: 1.2 blue device: 0.7 Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 11 / 12

Physical vs. simulated add test strip add test strip RIP RIP print extract color scale measure test strip predict colorimetry score color scale score color scale physical simulated Giordano Beretta (HP Labs) Color Imaging XVII EI 2012 paper 8292-32 12 / 12

Assessing color reproduction tolerances in commercial print workflow

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