Editing CD-R (section)

==Lifespan==
[[File:CD-R with degraded dye - 20080220.jpg|thumb|225px|An example of a CD-R burned in 2000 showing dye degradation in 2008. Part of the data on it has been lost.]]
Real-life (not accelerated aging) tests have revealed that some CD-Rs [[disc rot|degrade]] quickly even if stored normally.<ref>{{cite web | work=myce.com| url=http://www.myce.com/news/cd-recordable-discs-unreadable-in-less-than-two-years-6450 | title=CD-R Unreadable in Less Than Two Years| date=19 August 2003 | access-date=2007-02-01}}</ref><ref>{{cite web| url = http://www.pc-active.nl/toonArtikel.asp?artikelID=508 | work = PC-Active.com via archive.org | access-date = 2007-02-01 |archive-url = https://web.archive.org/web/20050309065410/http://www.pc-active.nl/toonArtikel.asp?artikelID=508 | archive-date = 2005-03-09 | title = CD-R's binnen twee jaar onleesbaar; Steekproef levert verontrustende resultaten op |trans-title=CD-Rs within two years unreadable; Sample produces troubling results | language = nl | date = August 19, 2003 | first = Jeroen | last = Horlings }}</ref> The quality of a CD-R disc has a large and direct influence on longevity—low-quality discs should not be expected to last very long. According to research conducted by J. Perdereau, CD-Rs are expected to have an average life expectancy of 10 years.<ref>{{cite web |url=http://www.ina.fr/video/3571726001/20-heures-emission-du-3-mars-2008.fr.html |title= Journal de 20 Heures |access-date=March 3, 2008 |at=approximately minute 30 of the TV news broadcast}}</ref> Branding is not a reliable guide to quality, because many brands (major as well as no name) do not manufacture their own discs. Instead, they are sourced from different manufacturers of varying quality. For best results, the actual manufacturer and material components of each batch of discs should be verified.

Burned CD-Rs suffer from material degradation, just like most writable media. CD-R media have an internal layer of dye used to store data. In a [[CD-RW]] disc, the recording layer is made of an alloy of silver and other metals—indium, antimony, and tellurium.<ref>{{cite web| url=http://www.imation.com/products/cd-r_media/la_cdrw_technology.html| title=CD-R & CD-RW Media Technology Primer| work=imation.com| access-date=2007-05-06| archive-url=https://web.archive.org/web/20070302162443/http://www.imation.com/products/cd-r_media/la_cdrw_technology.html| archive-date=2007-03-02| url-status=dead}}</ref> In CD-R media, the dye itself can degrade, causing data to become unreadable.

As well as degradation of the [[dye]], failure of a CD-R can be due to the reflective surface. While [[silver]] is less expensive and more widely used, it is more prone to [[oxidation]], resulting in a non-reflecting surface. [[Gold]], on the other hand, although more expensive and no longer widely used, is an inert material, so gold-based CD-Rs do not suffer from this problem. Manufacturers have estimated the longevity of gold-based CD-Rs to be as high as 100 years.<ref>{{cite web|url=http://delkin.com/i-5937134-archival-gold-cd-r-300-year-disc-binder-of-10-discs-with-scratch-armor-surface.html|title=Archival Gold CD-R "300 Year Disc" Binder of 10 Discs with Scratch Armor Surface|work=[[Internet Archive]]|archive-date=September 27, 2013 |archive-url=https://web.archive.org/web/20130927170900/http://delkin.com/i-5937134-archival-gold-cd-r-300-year-disc-binder-of-10-discs-with-scratch-armor-surface.html }}</ref>

By [[Optical disc#Surface error scanning|measuring the rate of correctable data errors]], the [[Compact disc#Integrity|data integrity]] and/or manufacturing quality of CD-R media can be measured, allowing for a reliable prediction of future data losses caused by media degradation.<ref name=qpx-g>{{cite web |title=QPxTool glossary |url=https://qpxtool.sourceforge.io/glossar.html |website=qpxtool.sourceforge.io |publisher=QPxTool |access-date=22 July 2020 |date=2008-08-01 |ref=QPx-Glossary}}</ref>