[QUOTE][i]Originally posted by Halcyon [/i]
[B]>>I have all those diagnostic progs you mentioned
Did you have any help with them? If not at all, the reflective and/or dye layer are probably too far gone...
No - this is why I am reporting this problem - and how do you measure the reflective quality of the layer? I want to be able to quanitify this problem
>>Can reading a disc cause the cyanine dye to fade?
I haven't heard of such a phenomenon, but excessive heat could do damage to the dye layer. I doubt that this is possible with the read laser calibration, unless the laser power calibration is seriously broken and the drive keeps on re-reading the same spot over and over again.
The disc has been used in VCD drive (not pc) about 2 dozen times
Another problem altogether is high speed rotation (52x or faster) of the discs. On some unbalanced discs this can cause cracks and/or peeling, which can result in total data loss.
No obvious physical damage
>>Is it practicable to examine a disc under the microscope? I havent
>>one. What power would one need?
I don't have information on this type of forensic study. I don't know if it would reveal anything useful without lots of heuristic knowledge about broken cd-r discs.
>>A pal of mine is also experiencing the same drop in reliability in his
>>collection after a year some have become unplayable (he's got 100's)
This is more than often the result of using the cheapest (and often very unreliable) media, sometimes in combination with inadequate handling (uv, heat, humidity, abrasion). I'm not blaming you or your friend for these things, but these are quite often major cause in my experience.
We get ambient temps here of up to 35C. I daresay that the media was cheap in the first place. If this is the case I want to be able to identify cheap media. It looks the same as a Princo for example. If its that cheap and nasty you can be sure it will find its way onto the market being passed off as a more expensive product. Its a national sport here - counterfeiting