years of lightfastness
Lightfastness tests simulate long-term indoor storage of a photo under normal fluorescent lighting and not exposed to direct sunlight.
Factors in addition to light as well as ozone, heat and humidity that can result in discoloration over an extended period are present.
ColorFast ink exhibited particularly excellent lightfastness due to its
resistance to discoloration resulting from these various factors.
- Storage conditions: Stored in a picture frame with glass, under indoor fluorescent lighting conditions.
- Media: double-weight matte roll / fine art paper roll
- The number of years stated above is the result of accelerated testing performed by Epson, but does not represent a guarantee.
- The number of years stated above does not apply to discoloration of the paper or lightfastness of the paper itself.
Evaluation methodology / lifetime estimation
- Evaluation conditions
Light source: White, fluorescent lighting (70,000 lux); Temperature: 24 degrees centigrade; Humidity: 60%
On top of the sample, a layer of air and 2-mm-thick soda-lime glass
The limit point is integrated illumination whose reflection OD value (1.0) declines by 30 % (OD = 1.0 >> 0.7). This means thet when the optical density as measured by a reflection densitometer is reduced by 30%, the sample is considered to be at the fading point.
- Lifetime estimation: 500 lux x 10 hours is treated as average daily dose under indoor fluorescent lighting.
Lifetime (in years) = cumulative illumination / (5000 lux / hour x 365)
Note: If you expose the sample to 70,000 lux for 24 hrs., that is the equivalent of 336 days of exposure at 500 lux for 10 hrs/day. Thus, 1 day of exposure = approximately 1 year of aging.