The Effects of Clear Toner on the Color

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# 4 CC 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 • ECI 2002 R 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)

Gretag. Macbeth™ Color. Checker

Calculations ΔE = √(L 1 -L 2)2 + (a 1 -a 2)2 + (b 1 -b 2)2 = √(39. 79 -L 2)2 + (15. 83 -a 2)2 + (18. 12 -b 2)2 = √(39. 79 -44. 01)2 + (15. 83 -16. 07)2 + (18. 12 -17. 5)2 ΔE = 4. 27 ΔL = (L 1 -L 2) =(39. 79 -44. 01) = -4. 22 ΔC = √(a 12+b 12) - √(a 22+b 22) = √(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

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

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, -6. 7

Special Thanks • Mark Gundlach and Michelle De. Fouw, X-Rite • Dr. Fleming • PCI Department

Thank You! Questions?