Thanks for the feedback, everyone. It makes me feel better about printing on DVDs. Now as for CDs, I'm curious...
Before the advent of direct inkjet printing on CDs, I read lots of testimony from people who burned CDs; and after six months or a year, the data on them was unreadable. People then started posting hints about how they avoided this: don't buy certain cheap CDs, don't place adhesive labels on CDs, buy CD-Rs instead of CD-RWs, store CDs properly - in individual cases, upright, and away from direct sunlight, etc.
Has anyone found that the special coating on printable CDs gives them an extra benefit because it provides more stability or protection to the CD, making it last longer? I wonder if anyone has noticed a quality difference between regular CD-Rs and -RWs (without an adhesive label) and those that are printable, especially if they're of the same brand. Just curious.
BTW, CDan, just as an aside, that report I quoted on care of CDs/DVDs mentioned something called pit art: "an alternative to printing that makes a holographic image on the disc; because itâ€™s inkless, balance & flatness arenâ€™t compromised." However, this is a 2003 report; so I don't know if pit art was (or is) "the norm" in DVD manufacturing, or if silkscreening is now the norm.
Maybe DVDs aren't as sensitive as they were in 2003 and/or ink isn't as much of an issue. That's why I'm a fan of practical experience for learning about what really works.