In order to renew this interesting discussion about aging of burned medias
stopped here since the end of July ...
I hope you know about these long lasting and official accelerated aging tests
conducted by the GIPWoG:
"Government Information Preservation Working Group"
for the NIST: National Institute of Standards and Technology:
I extracted here file the information about the test conditions
from their report published on december the 9th 2004:
to make this info clearly visible to all:
The only thing I find annoying with this official and long lasting tests in that they have not put out any pratical information for users about for example
which labels or MID codes
passed these tests better than others ...
If anybody finds anything practical like that it in all the information they put on-line please tell us !
Their next meeting will be on October 5th, 2005 at the Library of Congress !!
That's more or less the only practical info I could find ...
Temperature and humidity:
A Blue M (model: FRM-256B)1 environmental chamber was used to control the temperature and relative humidity through various settings of temperature ( ?
18 °C to ?
93 °C) and relative humidity (5 % to 98 %). The specified control accuracy is ±0.5 °C for temperature and ±1 % for rela-tive humidity (RH) respectively. The test stresses of aging used are given in Table 1.
A complete incubation cycle for temperature and RH accelerated testing is shown in Fig. 1. Once at the stress condition, the temperature and RH were held constant for a period of approximately 45 h followed by a gradual return
to ambient conditions. Discs were analyzed after each incubation cycle. This cycle was repeated under the same stress condition until the error rate of most discs in the group increased to exceed an upper limit of the error rates (as indicated in the DVD and CD specifications) or until the disc became unread-able.
A light chamber was designed and built at NIST to meet the requirements for controlled light exposure (Fig. 2).
Two cylindrical light bulbs were placed vertically in the center of the chamber, with up to twelve discs placed at equal distance from the light source. Intensity was measured at each disc location to check uniformity. The discs were installed with the recordable side facing the light source.
Two 150 W metal halide (M-H)  bulbs were used for the light source, giving a 47.5 mW/cm2 light inten-sity at the disc surface. Light intensities were measured using a Scientech Victor S310 thermo-power meter with shield tube. The wavelength range of the metal halide lamps is similar to sunlight, centered at 500 nm, and partly extending to UV region.
Disc Analyzers: In order to monitor the change in the error rate during aging, discs were analyzed after each incubation cycle using disc analyzers. A CD-R analyz-er capable of reading BLER (in the case of CD) and a DVD-R analyzer capable of reading PI error was used.
DVD-R Analyzer: The DVD 1000P analyzer con-forms to DVD specifications and was capable of testing electrical, digital, and mechanical parameters in DVDs, including PI errors, PO errors and jitter.
CD-R Analyzer: The CD CATS SA3 Advanced allowed measurement of all relevant CD disc parame-ters including BLER, E32 errors and jitter. All measure-ments are performed according to optical disc industry standards.
Fig 2 - Chamber for controlled light exposure