The Effects of Clear Toner on the Color Gamut of a Digital Press Robert Grotans Western Michigan University December 7, 2010

Overview Background Experimental Results Conclusion

Understanding Color Illuminant + Sample Spectrum + Standard Observer

What is “Color Gamut”? 1931 x, y Chromaticity Diagram

Profiling 1. Calibrate your device 2. Print, display, or scan a test chart 3. Measure the test chart 4. Use profiling software 5. Produce a profile

Experimental List of Substrates Substrate Name GSM 1 20# Hammermill Bond 75 2 24# Beckett Writing (super smooth) 90 3 60# Husky Opaque Offset 89 4 60# 4CC Storaenso Cover 160 5 80# Sappi Flo Gloss Digital Text 118

1. Calibrate The Device Shading Correction Gradation Auto Adjust Fiery RIP Calibration

2. Print a Test Chart ECI2002R CMYK test chart

3. Measure the Test Chart

4. Use Profiling Software

5. Produce a Profile Install profile Verify profile for accuracy

Analysis Gamut Comparison LAB Value Comparison (39.79, 15.83, 18.12) (44.01, 16.07, 17.5)

GretagMacbeth™ ColorChecker

Calculations ΔE = √(L1-L2)2 + (a1-a2)2 + (b1-b2)2 ΔL = (L1-L2) = √(39.79-L2)2 + (15.83-a2)2 + (18.12-b2)2 = √(39.79-44.01)2 + (15.83-16.07)2 + (18.12-17.5)2 ΔE = 4.27 ΔL = (L1-L2) =(39.79-44.01) = -4.22 ΔC = √(a12+b12) - √(a22+b22) = √(15.832+18.122) - √(16.072+(-17.5)2) = 0.3

Sample 1 – 20# Hammermill Bond Without 312,879 With 228,669

Sample 2 – 24# Beckett Writing Without 322,846 With 255,525

Sample 3 – 60# Husky Offset Without 338,949 With 239,272

Sample 4 – 60# Cover Without 404,957 With 267,681

Sample 5 – 80# Gloss Text Without 330,186 With 242,463

Clear Toner Over Vs. Clear Toner Under LAB Values Clear Toner Over Vs. Clear Toner Under Substrate ΔE ΔL ΔC 1 3.18 -1.87 1.08 2 2.47 -1.19 0.31 3 1.54 -0.06 0.17 4 3.11 -1.88 0.74 5 2.15 -0.58 1.15

Without Clear Toner Vs. Clear Toner Over LAB Values Without Clear Toner Vs. Clear Toner Over Substrate ΔE ΔL ΔC 1 4.78 -0.59 -3.20 2 4.60 -2.46 -3.01 3 7.22 -1.65 -4.29 4 6.86 -1.74 -3.68 5 4.75 -1.42 -2.81

Conclusion Not a lot of difference between clear toner over or under Clear toner originally reduced the color gamut by 20-35% Knowledge gained Recommendations Paper Original Clear Toner New Clear Toner 94.7, 2.1, -7 88.3, 1.8,-6.2 92.1, 2.1, -6.7

Special Thanks Mark Gundlach and Michelle DeFouw, X-Rite Dr. Fleming PCI Department

Thank You! Questions?