In my opinion one of the biggest killers of data on CD/DVD discs is excessive weight on top of discs. I'm not saying this is your case greaser but may I ask how you store your discs?
In my opinion even discs that had excessive weight on top of them prior to burning (excessive weight at the vendor) and seem to burn OK have a better chance of loosing data in the long term. Think about it, tiny little pits that have dye in them sandwiched between a couple of fragile layers of thin plastic. Not only has the dye have to remain the correct colour shade but also the laser has to track the little pits very accurately while spinning at high RPM. Not much room for error.
The average human hair is around 100 microns. The track pitch on a 4.7 GB disc is 0.74 microns. Not much room for error with DVD-R tracking.
1) No weight on top of discs.
2) No direct sunlight on discs.
3) Room temperature only.
4) Handle discs only by outer edges.
5) No stickers or ink on discs.
6) When not in use store in clam shells.
- That kind of stuff.
Would I trust my DVD player to accurately track 0.74 micron pits while spinning at a very high rate of speed? Discs that had a huge amount of weight on them?
The recording side of a DVD-R and DVD+R disc is a sandwich of a number of layers. First comes a polycarbonate plastic substrate containing a shallow spiral groove extending from the inside to the outside diameter of the disc. A DVD-R disc additionally includes pits and lands on the areas between the coils of the groove (land pre-pits). Added to this substrate is an organic dye recording layer (azo, cyanine, dipyrromethene or others) followed by a metal reflective layer (silver, silver alloy, gold). The dummy side of a single-sided disc consists of an additional flat polycarbonate plastic substrate (sometimes with an additional metal layer to obscure the bonding layer from view for aesthetic purposes). An adhesive then bonds two recording sides (for a double-sided) or a recording and dummy side (for a single-sided) together into the final disc. Some single-sided discs are also topped on the dummy side with decorations or additional layers that provide surfaces suitable for labeling by inkjet, thermal transfer or re-transfer printers.
The first step in manufacturing a DVD-R or DVD+R disc is to fabricate the polycarbonate plastic substrates (incorporating the spiral groove and land pre-pits) using an injection molding process. The dye is then applied using spin coating and the metal layers by means of DC sputtering. After both sides of the disc are completed they are bonded together using a hot melt, UV cationic or free radical process. Additional decoration or printable layers are typically applied using screen printing methods. A DVD-R (General) disc undergoes a further manufacturing step in which a specialized computer DVD recorder is used to prewrite information in the Control Data Zone of its Lead-in Area to inhibit direct copying of prerecorded DVD-Video discs encrypted with the Content Scrambling System (CSS). Apart from this, and some minor differences in the configuration of the molding stamper used to create the substrates, the process for manufacturing DVD-R and DVD+R discs is virtually identical.
Again, not saying this is greaser's problem. Maybe TY discs have gone down to landfill quality in the last couple years? If so I'm glad I'm still using verb AZOs.
I'm just bringing attention to how sensitive discs are and should be treated with great care.