10 Megalux-hour Progress and Time Off for Good Behavior
The first batch of 20 samples I listed in my news post on January 1, 2008 reached the 10 Megalux-hour exposure level in light fade testing last week. They have been measured, and small yet real changes have occurred. Of particular interest with respect to optical brighteners in inkjet papers is the fact that a loss of fluorescence has already happened in the OBA-containing test samples. Evaluation under blacklight illumination and measurements with a spectrophotometer easily confirm the subtle paper "yellowing" which is a consequence of the loss of OBA activity. Yet OBA fading is not the only change that has been detected. For example, the Epson R1800/ MIS R800 Ultrachrome Equivalent ink/ Epson Premium Luster Photo Paper combination demonstrates a small but noticeable loss of yellow colorant. The yellow colorant fading is especially affecting the light skin tone colors and the neutral gray patches in the test print. The R1800 does not use photo gray inks and thus prints composite grays by mixing cyan, magenta, and yellow inks. Loss of yellow colorant is causing a noticeable shift towards a cooler appearance in the light skin tones and gray scale patches. In contrast, the Epson R1800/ MIS R800 Ultrachrome Equivalent ink/ Red River Ultra Pro Gloss Plus is showing less fade at this point in test as are both R1800 samples made with the Epson OEM inks. It remains to be seen whether these early performance rankings will hold up as more light exposure accumulates.
I am putting some finishing touches on a comprehensive but hopefully user-friendly report format that will consolidate each test sample's performance into an individual PDF document. AaI&A members will be able to access all PDF reports and view them with the free Adobe Reader software. The reports will be updated routinely as the tests progress and multiple measurements are made. The PDF reports also have some innovative features that have taken additional time to perfect, otherwise I'd have posted a sample or two already.
Rest assured that while I am taking a short time off for good behavior, the testing continues! The first batch is back in test and well on the way to the 20 Megalux-hour exposure mark. A second batch of 20 new product combinations is also ready to begin testing.