Message-Id: <199905171809.LAA13750@dns.ccit.arizona.edu> Date: Mon, 17 May 1999 09:58:36 -0700 From: Bob Savage <mailto:bsavage@STANFORD.EDU> Subject: Re: CDs v. photo CDs - longevity To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU
Trudy Levy <mailto:iminteg@sirius.com> 05/14 11:07 wrote: > PhotoCDs do have a different storage medium ( gold I think) then most CD-ROMs,
> but the Real point of PhotoCDs is their special scanning and compression
> technologies not their storage durability.
to which David Adams responded: > As I understand it, the longevity of data on both CD media, Kodak Writeable CD (CD-R) and Photo CD Media are the same.
>
> 'When appropriately stored (in the dark, 25 degrees C, 40% RH) the data life model (at a 95% confidence level) predict
at data lifetime of 217 years'. >
> This is quoted from "Lifetime of Kodak Writeable CD and Photo CD Media"
> http://www.cd-info.com/CDIC/Technology/CD-R/Media/Kodak.html
>
> Be interesting to know what life expectancy other CD media is predicted using the same model ie. TDK, Sony etc.
The gold alluded to above is the color of the dye used (which is "burned" into in the recording process). The quality of this dye DOES affect longevity. The Kodak CDs tend to have better life expectancy than a lot of other brands and a good part of that is that they use Gold dye (others use cheaper techniques). IMO, it is well worth paying the extra money for the Kodak CDs (or another high quality CD, that is one which is made with gold dye; it is possible that a company has both gold-dye CDs and some other kind, so be careful when purchasing. TDK I believe uses blue and green dyes. Supposedly the green dye is pretty good, but it turned out to be incompatible with our first burner and I have never tried it again.)
Best of luck,
Bob Savage Media Preservation Unit Stanford University Libraries