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I just received the report, "Measures of CD-R Longevity" from Jerome L. Hartke, President, Media Services, Inc. In the event you didn't get one and wish one, his website is http://www.mscience.com It covers a series of tests they ran. Maddeningly, no specific products are identified. He gives his reasons. Given the design of the tests, he's probably right. It's quite short and, I think, well worth reading. Be advised that he offers his lab's services to evaluate CD longevity. One important conclusion is that BLER is not a valid universal measure of quality. His reasoning is included. However- this wouldn't be from me if there was no however: Why not design the tests to be able to isolate data related to each manufacturer's product? I feel very strongly that testing various dyes should be coupled with how the discs are surfaced. The speed at which discs are recorded is another variable. Cheap CDs have been widely reported to loose their lacquer before any significant data could be gathered on other longevity issues. The mating of reflective surface and its protective coating make every combination so different from the others that each is a unique product and should be so tested. Lumping them together makes no sense to me at all. From the description, I have no idea if reinforced gold, reinforced silver, ink-jet printable white CDs were included or not., never mid how they survived the testing. From the what-shall-we-use standpoint, we know little more from this paper than we did before. The results seem to be further blurred by the use of generic error correction systems even though there are usually significant differences by CD player and tester brand and model. Perhaps the information I'm looking for is included in the results and I'm just not able to recognize it. There is one confusing paragraph, "Longevity results were not the same for all discs. Significant differences were observed between manufacturers and also between samples [my question: of the same product? If more than two, should the word be "among?" Does this imply two samples?} from the same manufacturer. No clear differences were observed between dye types within the limited sample [quantity of samples are not specified.] Degradation was more severe for discs of very poor initial quality than for high quality samples, indicating that initial recorded [should this be record?] quality was important to longevity for multiple reasons. It's this last sentence that confuses me. Quality of recording is not mentioned elsewhere, as far as I can tell. This is the first time this undefined concept has been set forth in any of the CD tests I've looked at. Perhaps he means quality of the record. If so, I'd love to know how this ranking was decided upon. Steven Smolian
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