Dee once bubbled...
Really? I'll have to do some research on that...thanks.
There's also pitfalls in the digital archiving process in terms of data formats: it will cost you time, effort and money to make sure that as your old PC gets upgraded every few years that all of your CD's are forward-compatible for:
1) physical format of the storage media
2) data format of the image file
3) compatibility of the reader application to your OS.
For example, let's take a disk that you saved years ago in Adobe Photoshop 2.0
Q1: Hey, where's my 5.25" floppy slot? Dang! Okay, let's say that it was new enough that you put it onto a CD: what format was the CD done in? High Sierra? Can your current PC even read the CD? Maybe, maybe not
Q2: Okay, you passed through that gate and you can see files on the CD (and they're not corrupted, etc). You crank up your current version of Photoshop, CS. CS is roughly the 8th revision; does it still offer the feature of being backwards-compatible to the ancient Photoshop 2.0 format you saved them in way-back-when? If so, you're still in business...for now: maybe the next revision of Photoshop won't support that format anymore.
Q3: But let's say that it doesn't. Fortunately, you anticipated this problem and saved a copy of the original Photoshop 2.0 Application on the CD with the image files as a "just in case". So you doubleclick the Application - - - Dang, it was a Windows 3.1 application and it doesn't run under your current OS. Whoopsie.
Granted, all of these problems are solvable by maintaining your CD collection with up-to-date formats and applications, but this takes time and money to do. For most of us, its not going to be the cost to do this, but the physical time that's going to be our "gotcha". And if anyone doesn't believe me on this one, I have a photocopier box _full_ of 400KB 3.5" floppies that I'll pay you $.50 per disk to burn onto a CD for me.
Its getting a bit dated, but a good read on this subject is:
"Silicon Snake Oil: Second Thoughts on the Information Highway"
by Clifford Stoll
-hh