(Untitled)

[jmadd84]

I just gained an interesting skill... Like many people, I've always been able to estimate how much of a CD/DVD-R has been used by simply glancing at the media, and viewing the area that has been discolored by burning, but now, after much ripping, I have learned how to spot a manufactured single-layer video DVD from a dual-layer DVD; just look for

Comments

[sharikkamur]

One possibility that comes to mind is that given that a dual-layer disc has two layers then the light reflected from the bottom layer may be split by the upper layer acting as a diffraction grating, giving you a reflection off the top layer and then a seperate spectrum from the diffracted lower layer reflection.