Compact disc bronzing

At the time, PDO was contracted by several record companies, many of whose records may be affected. According to a list compiled on Classical.net and other sources, these include Ace Records, Albany Records, Appian Records, APR, Archiv Produktion, ASV Records, Baseline Records, Cala, Chapter 22 Records, Collins Classics, CRD Records, Danacords, Decca, Deutsche Grammophon, Globe Style, Hyperion Records, IMP records, L'Oiseau-Lyre, London Records, Memoir Records, Pearl Records, RPO Records, Testament Records and Unicorn-Kanchana. ==Preventing bronzing==

Bronzing is due to a fault in the manufacturing process and can therefore neither be prevented nor be stopped once it has begun. However, storage conditions certainly seem to contribute to the speed of the decay, as some bronzed CDs were already reported as unreadable in the mid-1990s, whereas others were still playable as recently as 2012. As it was noted that CDs stored in paper sleeves were deteriorating sooner and faster than CDs stored in jewel cases, it is likely that storing CDs in an acid-free environment might slow down the bronzing effect. A minimum measure would be to remove the booklet and paper inlay from the CD's jewel case, though it might be advisable to store affected CDs in envelopes made of alkaline paper inside a box made of acid-free cardboard. Plastic or vinyl sleeves are not considered safe because the softening agents in the plastic may lead to further corrosion; polypropylene sleeves are a notable safe exception. Similar measures are used for books suffering from acid deterioration. Because the recording is in the polycarbonate, not the reflective layer, the IASA has pointed out that in principle it would be possible to split the sandwich and re-coat the polycarbonate with aluminium to conserve the data on the disc. ==Customer support policy==

When the problem became known in the early 1990s, PDO offered to replace any discs thus affected if supplied with the defective disc and proof of purchase, and pledged to re-press new CDs until the year 2015 if a customer notices the corrosion problem. However, after a change of ownership, PDO (now EDC – Entertainment Distribution Company) discontinued its helpline in 2006, and defective CDs are now no longer replaced by the manufacturer, even though some of the affected record labels continue to offer replacement compact discs. == References ==