If you do use CDs or DVDs to backup your photo library – please read this.
After burning the disc, don’t label it. The top of the disc, NOT the bottom, is the most fragile part! Most damage comes from labeling the disc. The adhesives used in labels, and the dyes used in ink pens, are applied directly to the foil layer of the disc. If that gets damaged, you will be very unhappy.
I don’t put labels on my discs. I also don’t write on them. I simply put them into a sleeve or jewel case that has been labeled. Yes, the CD could become disassociated with the sleeve or case, but if that happens, I just need a second to read the disc to see what it contains. I can then resleeve and relabel it.
This system assures the best care of the fragile foil layerof the CD. But if you do apply a label to your CD, make sure to get one with acid-free materials. This will cost more but will last longer. Eventually, the adhesive will probably damage the CD, so make sure to backup your backup every few years as a precaution.
NOTE: I have tested several special pens and adhesives that claim to offer a safe alternative for writing on CDs, etc. These are long-term tests that I started in 1997. So far, none of those claims has been true and all the products I started testing are now off the market. Approach these products with some caution and do your research.