A standard DVDR contains about 4.7GB. The Dual layer DVDR have a capacity of 8.5GB, not quite twice. A dual layer DVDR is actually a DVD with two optical layers on the bottom of the disc rather than the normal one layer. You can't see the difference because the layers are determined by focusing the laser at different depths inside the dye.
It appears that if you need more space than a standard DVD can supply you, simply use a dual layer disc, right? Hang on; this is where it gets tricky.
Service bureaus like dataDisc are often some of the first users to find out how good a new technology really is. When the first dual layer discs hit the market, folks like us were reporting recording failure rates upwards of 50%. The technology is far improved from its early days. Now, failure rates are about where CDs failure rates are. Yep, you'll still get some "bad burns" but very few. It appears now that things are stable, everyone would like to use those recorders that have been shipping in home computers for several years now. Supplies of dual layer DVDs are much tighter than standard DVDs. So much so that even buying large quantities of dual layer discs will cost 4-10 times that of a standard DVD.
What does that mean for your next small run DVD project? Maybe nothing! On the other hand; it might actually be less expensive to do a 2 disc set. Make sure to do your homework!
by Al Foster, VP
dataDisc, Inc.
