{"id":614,"date":"2007-03-09T01:47:37","date_gmt":"2007-03-09T00:47:37","guid":{"rendered":"http:\/\/www.roumazeilles.net\/news\/en\/wordpress\/2007\/03\/09\/cd-da-life-duration\/"},"modified":"2007-03-09T01:49:32","modified_gmt":"2007-03-09T00:49:32","slug":"cd-da-life-duration","status":"publish","type":"post","link":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/2007\/03\/09\/cd-da-life-duration\/","title":{"rendered":"CD-DA life duration"},"content":{"rendered":"<p>In the context of the interest I have in evaluating the reliability of optical discs (more specifically CD-R and DVD-R whose use for archival purposes fully justify special attention), I found an interesting document published by the Electronic Library team of the French National Library (BNF).<\/p>\n<p><!--adsense#square_left-->The BNF is the recipient of the <em>legal deposit<\/em> in France and, in this context, archives all the Audio-CD (CD-DA) phonographic production since 1983. Alain Carou and Thi Phuong Nguyen summarized the observations made in this context, with two decennies of history. Overall, the resulting opinion is quite re-assuring since the CD-DA comply with their specification and promises (the most conservative estimations gave 20 years of shelf life for pressed optical CDs).<\/p>\n<p>Furthermore, the published report (titled &#8221; <a href=\"http:\/\/bibnum.bnf.fr\/conservation\/etudecdbnfjuin2005.pdf\">Contribution \u00c3\u00a0 l&#8217;\u00c3\u00a9tude du vieillissement des CD &#8211; Recherches sur les collections de la Biblioth\u00c3\u00a8que nationale<br \/>\nde France<\/a> &#8221; &#8211; French for <em>Contribution to the studies about CD ageing &#8211; Research about the collections at the French National Library<\/em>) finally contains many interesting observations and informations inside its 21 pages. In order to entice you, here are some of the elements I noticed:<\/p>\n<ul>\n<li>A clear explanation about the measurable parameters of CD quality (BLER, BERL, C1\/C2, <em>jitter<\/em>, etc.), in French.<\/li>\n<li>Detailled comments about the problems coming from silver+nitrocellulosic varnish discs (PDO UK discs known as &#8220;bronzed&#8221; or Optimes dics), where the varnish did not play its normal protecting role and let the silver layer corrode quickly (more quickly than in the case of aluminium layers).<\/li>\n<li>An analysis of &#8220;misted&#8221; discs where the polycarbonate substrate degraded much quicker than expected (bad chemical stabilization?).<\/li>\n<\/ul>\n<p>A must read.<\/p>\n<p>Source: <a href=\"http:\/\/bibnum.bnf.fr\/conservation\/supports.html\">http:\/\/bibnum.bnf.fr\/conservation\/supports.html<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the context of the interest I have in evaluating the reliability of optical discs (more specifically CD-R and DVD-R whose use for archival purposes fully justify special attention), I found an interesting document published by the Electronic Library team of the French National Library (BNF). The BNF is the recipient of the legal deposit [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18,30,34],"tags":[],"class_list":["post-614","post","type-post","status-publish","format-standard","hentry","category-culture","category-music","category-tech"],"_links":{"self":[{"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/posts\/614","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/comments?post=614"}],"version-history":[{"count":0,"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/posts\/614\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/media?parent=614"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/categories?post=614"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.roumazeilles.net\/news\/en\/wordpress\/wp-json\/wp\/v2\/tags?post=614"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}