Query about warped CDRs with sticky labels.

[Jay Pemberton]

Ever since the first times I saw the use of stick-on labels for CDRs I have been leery of them, knowing of the potential for tracking problems the added mass (and it's lack of accurate concentric balance atop a disc) can create for many CD players. (Not to mention those that have edges that don't stick down, or are falling/peeling off.) Lately I was going through many CDs I hadn't played in a long time, and a number of them were CDRs that had been given to me by various people. These discs bore stick-on labels. In auditioning them, I noticed a common problem: they would not play properly past the first one to three or four cuts. The sound started out bad, and went to worse. A quick look at each of them in profile showed me something that accounted for this tendency to only play the earliest parts. If you looked at them label side up, they all sported a very slight dish warp! It's not as though they were all left on a dashboard in the hot sun, they weren't. Most (IIRC) were always kept at room temperature, but are nonetheless warped. I understand the mechanics of why a dish warped CD behaves like this in a CD player; what I'm asking is, what is going on between the discs, and having these labels stuck on them, that is making them all warp in the same fashion?

[RedWallStudio]

My educated guess (I come from a pressure sensitive label background) is that the label is shrinking over time. Most of the labels are a "sandwich" type of construction: Paper on top, a layer of poly next and a layer of adhesive last. Unfortunately, these three layers are not very stable and can contract due to dry air and just normally over time. The adhesive just may be strong enough to warp the disc in the process.

Personally, I would never label a disc with a sticker for all the reasons you listed above. You can buy Inkjet printable CDs that work great with Epson (and other) printers, and they look a hell of a lot more pro.