I just prefer to be on the safe side and not label them at all
What I do is just keep them in a jewel case and have the info in the jewel case.
To save space I have recently been putting 2 to 4 CDs in the jewel case (the inner ring keeps a small distance between them,) so in my “database” I just referred to the manufacturer of the disc–I mix different manufacturers.
I also kept a whole bunch in a spindle and resorted to SCRATCHING the CD info (Name/Number) in the inner ring with a sharp object.
The data actually “lives” on the label side of the CD. That’s where the pits are. So damage to the label side can be much worse than to the optical side. In fact if you try–you can easily peel off the shiny reflective surface right off! Once you scratch it, it just FLAKES off!
Printing done during the manufacturing process is one thing, but applying labels and certain markers can cause deterioration of the reflective coating.
I know some markers are considered safe. I hope the inkjet inks are safe as well. But the way I see it, the less you do and handle the disc the safer the data is.
Labels are extremely dangerous because the adhesive materials can be unstable and “melt” over time as so many labels, tapes, do. Also, labels placed on one side can unbalance the disc, and full labels make the disc slightly heavier which might affect something. I’ve even read about the distribution of INK affecting the balance of the disc. Those discs spin faster than a HD, and the smallest imbalance can cause too much vibration. Don’t know about the validity of this but it sounds plausible.
Of course if you are giving people copies of stuff, and you don’t care too much then anything goes, but with the stuff I want to archive I’m just insanely cautious. I don’t need pretty labels–Too much work to make them anyway–I just need a number so I can match them up with my “database”…