Digital Hardcopy Xenon Light Stability Test Report for Mohawk Fine Papers, Inc. Andrea Venosa Image Permanence Institute Rochester Institute of Technology 7 Lomb Memorial Drive Rochester, NY 14623-564 (585) 475-5199 (585) 475-723 (Fax)
Introduction Mohawk Fine Papers, Inc. contracted with the Image Permanence Institute (IPI) to run comparative xenon light stability tests on a target (ink/media combination) provided by them to be exposed in two independent arrangements: with UV glass or without glass. Procedure Light stability studies were conducted on one digital print (one ink/paper combination), simulating daylight through window glass for approximately 5 years. For this test, a Q-Sun Xenon Test Chamber with an illumination intensity of 5 kilolux was used. Window-Q filters were placed between the xenon lamps and the samples. The prints were exposed to the high-intensity xenon light for a total of 82 days in two different settings: with UV filtering framing glass or without framing glass. Eighty-two days of constant, high-intensity exposure is approximately equivalent to 5 years of display under daylight through a window, assuming a typical display intensity of 45 lux for 12 hours per day. Samples were placed on the specimen tray mounted in holders. The samples placement on the tray was rotated weekly to account for the asymmetry of the position of the light source with respect to each sample. The temperature and humidity across the specimen plane were 7 F ±5 F and 5% RH ±3% RH.. The following sample names were provided by Mohawk Fine Papers, Inc. and will be used throughout this report: Strathmore Pure Cotton Inkjet, Clean White Hot Press Smooth 3 gsm / 9-ink Epson Ultrachrome HD / No glass Strathmore Pure Cotton Inkjet, Clean White Hot Press Smooth 3 gsm / 9-ink Epson Ultrachrome HD / With UV glass Test targets consisting of cyan, magenta, yellow, red, green, and blue patches each at ten levels of darkness, and black patches at twenty levels of darkness in roughly equal increments, were provided by Mohawk Fine Papers, Inc.. All target patches were measured in Status A visual, red, green, and blue
density using a GretagMacbeth Spectrolino spectrophotometer before testing and at one week intervals during exposure. In density mode, this device conforms to ANSI/NAPM Standard IT2.17-1995, ANSI/NAPM Standard IT2.18-1996, ANSI/NAPM Standard IT2.19-1994, ISO Standard 5-4:1995, ISO Standard 5-3:1995, and ISO Standard 5-2:1991. Sample patches were read in ANSI/ISO Status A visual, red, green, and blue as specified in ANSI/NAPM Standard IT2.18-1996 and ISO Standard 5-3:1995. Results for each material are based on the averages of the two replicates corresponding to each sample. The calculations used to determine the amount of colorant fading suffered by the samples during testing (calculated as percentage of change from original density) are described below: Percent Density Change in Pure Primary Color Patches a) Pure cyan: %DdC(R) t = [(dc(r) t - dc(r) ) dc(r) ] 1 b) Pure magenta: %DdM(G) t = [(dm(g) t - dm(g) ) dm(g) ] 1 c) Pure yellow: %DdY(B) t = [(dy(b) t - dy(b) ) dy(b) ] 1 Percent Density Change in Secondary (Mixed) Color Patches d) Magenta in Red: %DdR(G) t = [(dr(g) t - dr(g) ) dr(g) ] 1 e) Yellow in Red: %DdR(B) t = [(dr(b) t - dr(b) ) dr(b) ] 1 f) Cyan in Green: %DdG(R) t = [(dg(r) t - dg(r) ) dg(r) ] 1 g) Yellow in Green: %DdG(B) t = [(dg(b) t - dg(b) ) dg(b) ] 1 h) Cyan in Blue: %DdB(R) t = [(db(r) t - db(r) ) db(r) ] 1 i) Magenta in Blue: %DdB(G) t = [(db(g) t - db(g) ) db(g) ] 1 Percent Density Change in Composite Neutral Patch j) Cyan in neutral: %DdN(R) t = [(dn(r) t - dn(r) ) dn(r) ] 1 k) Magenta in neutral: %DdN(G) t = [(dn(g) t - dn(g) ) dn(g) ] 1 l) Yellow in neutral: %DdN(B) t = [(dn(b) t - dn(b) ) dn(b) ] 1 The calculations used to determine the color balance in neutral (composite neutral, gray) density patch (calculated as the percent of average density) are described below:
Percent Color Shift in Composite Neutral Patch a) Cyan-magenta shift: % dn(r-g) t = % dn(r) t - % dn(g) t b) Magenta-yellow shift: % dn(g-b) t = % dn(g) t - % dn(b) t c) Yellow-cyan shift: % dn(b-r) t = % dn(b) t - % dn(r) t The calculations used to determine the changes in d min are described below: Changes in d min a) Red density change: Dd min (R) t = d min (R) t d min (R) b) Green density change: D d min (G) t = d min (G) t d min (G) c) Blue density change: D d min (B) t = d min (B) t d min (B) Other than d min stain, all parameter calculations were performed for an initial density of.5 and 1.. The Standard does not specify applicable acceptable endpoints because the amount of image change that can be tolerated is subjective, and will vary with the product type and specific consumer or institutional requirements. The endpoints selected by IPI agree with the illustrative endpoints chosen by the ISO 1899:26. The overall predicted display life is based on the time to reach the first of the endpoints given below. Parameter Patch Endpoint Cyan fade Pure cyan 3% loss Magenta fade Pure magenta 3% loss Yellow fade Pure yellow 3% loss Black fade Pure black 3% loss Magenta fade Red 3% loss Yellow fade Red 3% loss Cyan fade Green 3% loss
Yellow fade Green 3% loss Cyan fade Blue 3% loss Magenta fade Blue 3% loss Cyan fade Composite neutral 3% loss Magenta fade Composite neutral 3% loss Yellow fade Composite neutral 3% loss Red-green color balance Composite neutral 15% change Red-blue color balance Composite neutral 15% change Green-blue color balance Composite neutral 15% change Parameter Patch Endpoint Cyan stain White +.1 Magenta stain White +.1 Yellow stain White +.1 Note that all the predictions are based on the following assumptions: 1. Only photochemical reactions are responsible for optical changes in the colorants. 2. The reaction rates are governed only by the amount of light. In other words, the rate-determining step depends only on the rate that photons are delivered to the reaction. 3. Light fading obeys reciprocity law. Reciprocity law says that the total chemical change is constant for a given constant exposure, independent of the intensity, where exposure equals intensity multiplied by time. 4. Only daylight used for typical display. 5. The intensity of the typical display condition is 45 lux. 6. The exposure time for typical display is 12 hours per day.
Results Predicted years to reach endpoints in the.5 density patches are given in the table below: Predicted Years to Endpoint.5 density patches Strathmore Pure Cotton Inkjet, Clean White Hot Press Smooth 3 gsm / 9-ink Epson Ultrachrome HD Sample Without glass With UV glass Cyan fade 21 47 Magenta fade 38 Yellow fade 13 33 Black fade 37 Magenta fade (Red) 38 Yellow fade (Red) 16 35 Cyan fade (Green) 24 Yellow fade (Green) 15 34 Cyan fade (Blue) 27 Magenta fade (Blue) 42 Cyan fade (neutral patch) 31 Magenta fade (neutral patch) 47 Yellow fade (neutral patch) Red-green color balance Red-blue color balance Green-blue color balance Predicted years to reach endpoints in the 1. density patches are given in the table below:
Predicted Years to Endpoint 1. density patches Strathmore Pure Cotton Inkjet, Clean White Hot Press Smooth 3 gsm / 9-ink Epson Ultrachrome HD Sample Without glass With UV glass Cyan fade 24 Magenta fade Yellow fade 2 Black fade Magenta fade (Red) Yellow fade (Red) 37 Cyan fade (Green) 46 Yellow fade (Green) 25 Cyan fade (Blue) Magenta fade (Blue) Cyan fade (neutral patch) Magenta fade (neutral patch) Yellow fade (neutral patch) Red-green color balance Red-blue color balance Green-blue color balance None of the materials reached endpoint criteria for d min density gain. Discussion and Conclusions Measurements Colorant Fade. The sample tested, Strathmore Pure Cotton Inkjet, Clean White Hot Press Smooth 3 gsm / 9-ink Epson Ultrachrome HD, reached its endpoint due to colorant fade in both exposure configurations (without glass and
with UV glass). Although UV glass mitigated the effect of light considerably, it was not enough to prevent the sample from reaching the endpoint. See Appendixes A and B for graphs. Stain. Th sample did not show significant signs of staining (discoloration of the media) during the light exposure. See Appendix C for graphs. Color Balance. This parameter is analyzed with the purpose of determining the degree to which image neutrality has been affected due to light fading. There should be a relatively equal colorant loss (cyan, magenta and yellow) for the image to remain neutral. When this loss is unequal (crosses the ±15% limit), the image will exhibit a specific color cast, and original colors may show shift in hue. The sample did not reach an endpoint for color balance during the exposure. See Appendixes A and B for graphs. Visual Observations The visual assessment of all the samples matched the numerical interpretations for the color patches. Overall Life Expectancy The following table indicates simulated years of exposure to reach the first endpoint. Predicted Years to Reach First Endpoint Sample Image area (.5 density) Image area (1. density) Without glass 13 24 With UV glass 33 >5 It must be understood that these results pertain exclusively to the particular array of materials tested including printer, colorant, and media.
Appendix A Graphs of Densitometry-based Changes in Samples during Exposure in Patches.5 Density Units
Percent Cyan Colorant Retention in.5 Density Pure Cyan Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Cyan Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Magenta Colorant Retention in.5 Density Pure Magenta Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Magenta Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Yellow Colorant Retention in.5 Density Pure Yellow Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Yellow Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Black Colorant Retention in.5 Density Pure Black Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Black Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Magenta Colorant Retention in.5 Density Red Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Magenta Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Yellow Colorant Retention in.5 Density Red Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Yellow Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Cyan Colorant Retention in.5 Density Green Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Cyan Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Yellow Colorant Retention in.5 Density Green Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Yellow Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Cyan Colorant Retention in.5 Density Blue Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Cyan Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Magenta Colorant Retention in.5 Density Blue Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Magenta Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Cyan Colorant Retention in.5 Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Cyan Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Magenta Colorant Retention in.5 Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Magenta Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Yellow Colorant Retention in.5 Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Yellow Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Red Green Color Imbalance in.5 Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 1 8 6 Percent Red Green Color Imbalance 4 2-2 1 2 3 4 5 6 Endpoint +15% Endpoint -15% -4-6 -8-1
Percent Red Blue Color Imbalance in.5 Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 1 8 6 Percent Red Blue Color Imbalance 4 2-2 1 2 3 4 5 6 Endpoint +15% Endpoint -15% -4-6 -8-1
Percent Green Blue Color Imbalance in.5 Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 1 8 6 Percent Green Blue Color Imbalance 4 2-2 1 2 3 4 5 6 Endpoint +15% Endpoint -15% -4-6 -8-1
Appendix B Graphs of Densitometry-based Changes in Samples during Exposure in Patches 1. Density Units
Percent Cyan Colorant Retention in 1. Density Pure Cyan Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Cyan Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Magenta Colorant Retention in 1. Density Pure Magenta Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Magenta Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Yellow Colorant Retention in 1. Density Pure Yellow Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Yellow Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Black Colorant Retention in 1. Density Pure Black Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Black Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Magenta Colorant Retention in 1. Density Red Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Magenta Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Yellow Colorant Retention in 1. Density Red Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Yellow Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Cyan Colorant Retention in 1. Density Green Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Cyan Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Yellow Colorant Retention in 1. Density Green Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Yellow Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Cyan Colorant Retention in 1. Density Blue Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Cyan Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Magenta Colorant Retention in 1. Density Blue Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Magenta Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Cyan Colorant Retention in 1. Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Cyan Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Magenta Colorant Retention in 1. Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Magenta Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Yellow Colorant Retention in 1. Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 12 1 Percent Yellow Colorant Retention 8 6 4 Endpoint 7% 2 1 2 3 4 5 6
Percent Red Green Color Imbalance in 1. Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 1 8 6 Percent Red Green Color Imbalance 4 2-2 1 2 3 4 5 6 Endpoint +15% Endpoint -15% -4-6 -8-1
Percent Red Blue Color Imbalance in 1. Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 1 8 6 Percent Red Blue Color Imbalance 4 2-2 1 2 3 4 5 6 Endpoint +15% Endpoint -15% -4-6 -8-1
Percent Green Blue Color Imbalance in 1. Density Neutral Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH) 1 8 6 Percent Green Blue Color Imbalance 4 2-2 1 2 3 4 5 6 Endpoint +15% Endpoint -15% -4-6 -8-1
Appendix C Graphs of Densitometry-based Changes in Samples during Exposure in d min
Cyan Stain in Dmin Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH).2.16 Red Density Change.12.8 Endpoint.1.4 1 2 3 4 5 6 -.4
Magenta Stain in Dmin Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH).2.16 Green Density Change.12.8 Endpoint.1.4 1 2 3 4 5 6 -.4
Yellow Stain in Dmin Patch During Exposure to 5 Kilolux Filtered Xenon Arc Light (25ºC and 5%RH).2.16 Blue Density Change.12.8 Endpoint.1.4 1 2 3 4 5 6 -.4