The optical characteristics of the phthalocyanine dye are critical in the recording process. A small change in the absorbance properties of this material can result in a disk error. The photosensitivity of the cyanine and phthalocyanine dyes may be an issue in the archival stability of CD-R media. Cyanine and phthalocyanine dyes are organic materials that may be subject to damage under blue or UV lighting conditions. Anecdotal reports by 3M researchers suggest high block error rates when CD-R disks are exposed to sunlight.
Speed is clearly a critical issue for certification in an archival application.
When using single and double speed access, virtually all manufacturers seem to assume that the Orange Book standard is adequate. However, at higher speeds, it is not so clear. The faster speed means higher power on the laser, and an associated higher risk with the writing process. Yamaha has established a complete certification program for their 4xS disks and will certify other manufacturers disks. Both physical and logical standards for CD-recordable appear to be in a severe state of flux.