Based on Canon Inc. studies conducted using Canon Photo Paper Pro, under glass, utilizing industry-standard lighting conditions and controlled temperature and humidity. Results may vary based on individual environmental factors.
Accelerated test conditions on Photo Paper Pro
Canon Inc. Evaluation
Temperature: 24°C Humidity: 60%
Light source: White fluorescent light 70,000 lux
Layer of air and 2mm-thick glass on the sample
Presumed conditions: Assuming one day's illumination as 500 lux x 10 hours
In-House Evaluation Criteria (Based on ISO)
Single color/Composite color: A color change has occurred if the density is under 70% (OD from 1.0 to <0.7) Process Bk: The fading ratio between each color is within 15%, and a color change has occurred if the density is under 70% (OD from 1.0 to <0.7)
The 25 years of light-fastness may not be achieved depending on storing conditions. The expressed number of years is the result of simulated testing conducted by Canon Inc. and is not guaranteed. This number of years does not apply for paper fading or durability.
Based on Canon and Wilhelm Imaging Research studies conducted using Photo Paper Pro under glass with a layer of air, and industry fluorescent lighting conditions.

Accelerated test conditions: Photo Paper Pro
Wilhelm Imaging Research Inc. Evaluation
The 26-28 years of light-fastness--Accelerated fluorescent light fading test condition:
Temperature: 24°C Humidity: 60%
Light source: White fluorescent light 30,000lux
Glass above the sample
Presumed conditions: Assuming one day's illumination as 450lux x 12 hours
Canon Inc. Evaluation
Temperature 24°C Humidity: 60%
Light source: White fluorescent light 70,000lux
Layer of air and 2mm-thick glass on the sample
Presumed conditions: Assuming one day's illumination as 500lux x 10 hours
In-house Evaluation Criteria (Based on ISO)
Single color/Composite color: A color change has occurred if the density is under 70% (OD from 1.0 to <0.7)
Process BK: The fading ratio between each color is within 15% and a color change has occurred if the density is under 70% (OD from 1.0 to <0.7)
The 25 years of light-fastness may not be achieved depending on storing conditions. The expressed numbers of years is the result of simulated testing conducted by Canon, Inc. and is not guaranteed. This number of years does not apply for paper fading or durability.