How We Tested the Longevity of Inks
All photographs fade over time, as sunlight and pollution take their toll. But to determine whether printer manufacturers' inks last longer than those of third-party suppliers, researchers need to condense years of image fading into just a few days. How do they do it?
Technicians in the Imaging Products Laboratory at the Rochester Institute of Technology (RIT) place color prints in environmental chambers where they can accelerate the prints' exposure to ultraviolet light and ozone--the atmospheric pollutants responsible for sapping the color from graphics as years go by.
For this feature, RIT tested print samples from manufacturers' inks and from third-party aftermarket inks. Altogether, it tested ten cartridges per color, per vendor.
For the light-fastness tests, RIT technicians placed the print samples in a Xenon-arc chamber (see the image above) for 80 hours at 145 degrees Fahrenheit, exposing the samples to an increased level of ultraviolet light. In the chamber, brief bursts of high-intensity light mimic the effects of a low-intensity exposure over a period of many years.
The laboratory also ran tests to determine how well a print resisted the effects of ozone or pollution in the real world. In this test, RIT researchers measured the image's color values before and after a seven-day exposure to air containing 5 parts per million of ozone.