saving digital files onto CDs

[Saulius]

Those of you who digitally work your images and save them or back them up onto CDs here is an
article (http://customwire.ap.org/dynamic/stories/D/DISC_ROT?SITE=ORPOR&SECTION=HOME&TEMPLATE=DEFAULT) of interest. Just something to think about.

[Donal Taylor]

it rather like saying - we photographed our wedding on cheap East German 200 iso colour negative film we got cheap, stored it in a shoebox in our damp basement (cold in the winder, unbearably hot in the summer) and we also kept the prints in those "magnetic" page albums after we got them processed at the kwik-e-mart. Now the prints have all faded and when we went to get new ones they told us there was mould on the negatives and the colour had all faded...

You get what you pay for (cheap CD's cheap film) and if you store your film or CD's in poor conditions, you will reap what you sew.

So what's new?

[neil poulsen]

Scary! I didn't realize that the top layer is also fragile. I've got some music CD's that I would hate to lose.

I also wonder about the longevity of disks written on home computers, versus those produced commercially.

[RichSBV]

I haven't yet read the article, but yes, CD's are very fragile to specific types of damage. I just went though heck trying to replace a music CD that got cracked after I closed the player door and didn't realise that the CD wasn't on the spindle!

And it is that very thin top layer that is 'burned' when you make your own. A simple scratch will make the cd worthless. The best safety procedure there would be to use stick-on cd labels on top of the disk for added protection. I regularly burn cd's here and come up with occasional 'coasters'. I test these by bending and scratching. Very fragile to the right kind of force at the right point. A scratch on the clear side can sometimes be overcom. A scratch on the top surface can not be fixed...

And CD's are suseptible to their own kind of fungus that destroys the information stored on them. The same storage rules for fiilm should be applied to cd's...

Most commercial CD's are pressed like the old vinyl records and are a bit more durable...

[tim atherton]

"And it is that very thin top layer that is 'burned' when you make your own. A simple scratch will make the cd worthless. The best safety procedure there would be to use stick-on cd labels on top of the disk for added protection. "

No no NO! That's the worse thing - a) the glue can assist in causing the rot and other damage. b) More immediately, even the best home applied circular ones increase the error rate massively by unbalancing the CD c) if it ever gets wet or even damp it will unbalance it even more.

Same goes for not writing on the top layer

And store them the same way you would (should) film - moderate temperature and humidity, no hot/cold cycling, dark storage etc

The Kodak Gold CD's used to have a tougher lacquer layer on the top foil surface (along with the foil being gold based and the dye layer being much better and more stable than the competitors) - it was one of the reasons they called them "archival" (whatever that means). I'm not sure if the similar Matsui gold CD's also have that layer - but all other things considered they are the best option (Kodak licensed the production from Matsui, but may have added the lacquer as part of their own production).

I've done some work with the people who are examining the longevity of optical and magnetic media, as well as disaster recovery procedures for them (flood, fire etc etc). If I can find the basic information I have sent out in the past let me know and I can email it to you.

CD's can actually withstand a certain amount of damage because they use a triple (I think, maybe quadruple) redundancy in the recording process - sort of like a mini RAID array - that's why they will - up to a point - work with scratches etc.

[Jim Rice]

Do you guys have some set interval for duplicating CD-Rs?

[Phil_4244]

Good article on CDs. I'd like to hear from contributors that have recommended brands of CDs that they use specifically to store their digital photos. Also, I'd like to hear some ideas on labeling the CDs to prevent the possible damage that we are reading in this article. I will always use the "clear inner hub" as described in the article to label my CDs from now on. What brand of markers are you guys using too?

[Ron betcher]

Here are a couple of things that are interesting.

Beware it is a 50 page document.

http://www.itl.nist.gov/div895/carefordisc/CDandDVDCareandHandlingGuide.pdf

http://www.cdmediaworld.com/hardware/cdrom/cd_quality.shtml

And finally.... the largest site(if someone gets through all of it i would like a short summary) http://www.cdrfaq.org/faq.html