Editing Compact disc (section)

=== Integrity ===
CDs are susceptible to damage during handling and from environmental exposure. Pits are much closer to the label side of a disc, enabling defects and contaminants on the clear side to be out of focus during playback. Consequently, CDs are more likely to suffer damage on the label side of the disc. Scratches on the clear side can be repaired by refilling them with similar refractive plastic or by careful polishing. The edges of CDs are sometimes incompletely sealed, allowing gases and liquids to enter the CD and corrode the metal reflective layer and/or interfere with the focus of the laser on the pits, a condition known as [[disc rot]].<ref name="clir">Council on Library and Information Resources: [https://www.clir.org/pubs/reports/pub121/sec5.html Conditions that Affect CDs and DVDs] {{webarchive|url=https://web.archive.org/web/20160915012213/https://www.clir.org/pubs/reports/pub121/sec5.html |date=15 September 2016 }}</ref> The fungus ''[[Geotrichum candidum]]'' has been found—under conditions of high heat and humidity—to consume the polycarbonate plastic and aluminium found in CDs.<ref>{{Cite journal|url=http://www.nature.com/news/1998/010628/full/news010628-11.html|title=Fungus eats CD|year=2001|journal=Nature|doi=10.1038/news010628-11|url-status=live|archive-url=https://web.archive.org/web/20131212044729/http://www.nature.com/news/1998/010628/full/news010628-11.html|archive-date=12 December 2013|last1=Bosch|first1=Xavier |issn=0028-0836}}</ref><ref>{{cite news|url=http://news.bbc.co.uk/2/hi/science/nature/1402533.stm|title=Fungus 'eats' CDs|date=June 2001|publisher=BBC|url-status=live|archive-url=https://web.archive.org/web/20131212220948/http://news.bbc.co.uk/2/hi/science/nature/1402533.stm|archive-date=12 December 2013}}</ref>

The [[data integrity]] of compact discs can be measured using [[Optical Disc#Surface error scanning|surface error scanning]], which can measure the rates of different types of data errors, known as ''C1'', ''[[C2 error|C2]]'', ''CU'' and extended (finer-grain) error measurements known as ''E11'', ''E12'', ''E21'', ''E22'', ''E31'' and ''E32'', of which higher rates indicate a possibly damaged or unclean data surface, low media quality, [[disc rot|deteriorating media]] and [[CD-R|recordable media]] written to by a malfunctioning [[CD writer]].

Error scanning can reliably predict data losses caused by media deterioration. Support of error scanning differs between vendors and models of [[Optical disc drive#Appliances|optical disc drive]]s, and ''extended'' error scanning (known as ''"advanced error scanning"'' in [[Nero DiscSpeed]]) has only been available on [[Plextor#Optical drives|Plextor]] and some [[BenQ]] optical drives so far, as of 2020.<ref name=gleitz>{{cite web|language=de|url=https://gleitz.info/forum/index.php?thread/32049-philips-dvd-r-8x-infodiscr20/&postID=308650#post308650|date=2006-11-18|title=Philips DVD-R 8x (InfodiscR20) - Philips - Gleitz}}</ref><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>