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I remember back in, probably the late 1990s or early 2000s, when my org was scrambling to copy analog media to "immortal" digital CD-Rs. 20 years later, they w

I remember back in, probably the late 1990s or early 2000s, when my org was scrambling to copy analog media to "immortal" digital CD-Rs. 20 years later, they went into some of the archives to discover that most of the CD-Rs were unreadable. The material had degraded severely enough that the material had observable pits (holes) in them. Plan accordingly. Digital copies require it, too. Edit: https://en.wikipedia.org/wiki/Disc_rot https://en.wikipedia.org/wiki/Disc_rot

PaulHoule 4y ago
The dyes used in writable CD's are fairly long lasting, as are the dyes used in writable Blu-Ray. There are some writable DVD's which use a media similar to Blu-Rays but they are unusual. This book talks about the sordid story of fugitive color media: http://www.wilhelm-research.com/book_toc.html http://www.wilhelm-research.com/book_toc.html how wedding photographers got blindsided when, 20 years later, people discovered that Kodak prints and negatives of their special day were severely faded. Or how Hollywood woke up in 1980s and realized there was big money in old movies and went looking for a solution: early on there was the bad idea of splitting out the three colors into three separate wheels, but later people realized that color film lasts much longer if you keep it in the freezer.
- thatoneguy 4y ago
  The first organic dye (cyanine) used for CDRs back in the '90s rotted faster than the more expensive phthalocyanine (20-50 years vs 50-100 years)[1]. [1] https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/longevity-recordable-cds-dvds.html https://www.canada.ca/en/conservation-institute/services/con...
- dylan604 4y ago
  The separating into 3 B&W negatives of the RGB separations was (is?) still a thing. In 2012, I was involved in film restoration projects that used laser recorders to take the processed digital files to 35mm B&W negative. The fun begins on trying to restore from one of the archives. Film shrinks and at different rates depending on how they are stored. So scanning each of the R+G+B negatives is one things, but getting them stacked and aligned taking into account the distortion distinct to each frame x3 is just glorious!!
  - PaulHoule 4y ago
    That’s why you are better off keeping the negatives in the freezer
digitallyfree 4y ago
If your only digital archives are on cold media (e.g. optical disks, tape, offline HDDs) and are never replaced you have a problem. Keep them on readable hot storage that can be easily checked and upgraded over time and that should not be an issue. I've lost personal archives on CD-R/DVD-R myself and now I keep my archives stored hot on ZFS (has redundancy + bitrot protection), with additional hot and cold backups that are checked regularly. When disks fail they are quickly replaced, thus ensuring that the data is on relatively "new" as opposed to aging media. The article also mentions the problem with old/proprietary file formats for digital media which can't be opened in the future. Someone I knew actually had a story about how he had pictures stored in some obscure digital format (this was in the 90s when digital cameras were in their infancy) and he had to set up a equally old computer and software just to get the images reexported into something more modern. For something like this again regular checking of the archives (and keeping them hot) helps. Also I'm pretty sure the most basic standardized formats like BMP and JPG aren't going away for a long time.
- Roark66 4y ago
  It is interesting, could you say more on how old were CD-Rs that failed and what percentage roughly failed? Also how were they stored? I hear a lot of this information, but personally my experiences are diametrally opposite. I've never used cdrs to store really important data, I have all this on hdds, but about 30 20 year + old CDRs I recently found in my storage (stored in a dark cold - sometimes wet basement) are all fine. Same with hard drives that haven't been touched for the same amount of time.
  - digitallyfree 4y ago
    The CD-Rs were around fifteen years old, stored in plastic boxes in my house (in rooms with HVAC). A couple of them failed in a set of twenty or thirty I think. I do have 20+ year old CD-Rs that still work fine though. For hard drives I have had ones that were mysteriously corrupted after being unused for six years or so, but others that were readable after fifteen. It partially is the luck of the draw.
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PaulHoule 4y ago

The dyes used in writable CD's are fairly long lasting, as are the dyes used in writable Blu-Ray. There are some writable DVD's which use a media similar to Blu-Rays but they are unusual. This book talks about the sordid story of fugitive color media: http://www.wilhelm-research.com/book_toc.html http://www.wilhelm-research.com/book_toc.html how wedding photographers got blindsided when, 20 years later, people discovered that Kodak prints and negatives of their special day were severely faded. Or how Hollywood woke up in 1980s and realized there was big money in old movies and went looking for a solution: early on there was the bad idea of splitting out the three colors into three separate wheels, but later people realized that color film lasts much longer if you keep it in the freezer.

thatoneguy 4y ago
The first organic dye (cyanine) used for CDRs back in the '90s rotted faster than the more expensive phthalocyanine (20-50 years vs 50-100 years)[1]. [1] https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/longevity-recordable-cds-dvds.html https://www.canada.ca/en/conservation-institute/services/con...
dylan604 4y ago
The separating into 3 B&W negatives of the RGB separations was (is?) still a thing. In 2012, I was involved in film restoration projects that used laser recorders to take the processed digital files to 35mm B&W negative. The fun begins on trying to restore from one of the archives. Film shrinks and at different rates depending on how they are stored. So scanning each of the R+G+B negatives is one things, but getting them stacked and aligned taking into account the distortion distinct to each frame x3 is just glorious!!
- PaulHoule 4y ago
  That’s why you are better off keeping the negatives in the freezer

digitallyfree 4y ago

If your only digital archives are on cold media (e.g. optical disks, tape, offline HDDs) and are never replaced you have a problem. Keep them on readable hot storage that can be easily checked and upgraded over time and that should not be an issue. I've lost personal archives on CD-R/DVD-R myself and now I keep my archives stored hot on ZFS (has redundancy + bitrot protection), with additional hot and cold backups that are checked regularly. When disks fail they are quickly replaced, thus ensuring that the data is on relatively "new" as opposed to aging media. The article also mentions the problem with old/proprietary file formats for digital media which can't be opened in the future. Someone I knew actually had a story about how he had pictures stored in some obscure digital format (this was in the 90s when digital cameras were in their infancy) and he had to set up a equally old computer and software just to get the images reexported into something more modern. For something like this again regular checking of the archives (and keeping them hot) helps. Also I'm pretty sure the most basic standardized formats like BMP and JPG aren't going away for a long time.

Roark66 4y ago
It is interesting, could you say more on how old were CD-Rs that failed and what percentage roughly failed? Also how were they stored? I hear a lot of this information, but personally my experiences are diametrally opposite. I've never used cdrs to store really important data, I have all this on hdds, but about 30 20 year + old CDRs I recently found in my storage (stored in a dark cold - sometimes wet basement) are all fine. Same with hard drives that haven't been touched for the same amount of time.
- digitallyfree 4y ago
  The CD-Rs were around fifteen years old, stored in plastic boxes in my house (in rooms with HVAC). A couple of them failed in a set of twenty or thirty I think. I do have 20+ year old CD-Rs that still work fine though. For hard drives I have had ones that were mysteriously corrupted after being unused for six years or so, but others that were readable after fifteen. It partially is the luck of the draw.

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