CDR vs. DVDR

vbimport

#1

Does anyone know why CDR,s and DVDR,s are manufactured completely different. Most CDR,s are a single layer of plastic with the dye layer on top covered with a protective coating. All DVDR,s I have seen are two layers of plastic with the dye sandwiched between them.
Just curious I guess.


#2

Because CD-R is a different tech compared to DVD?!?


#3

I think they learned the lesson that the CDR structure had this very annoying flaw, which is that damage to the top layer leads to unreadable discs. The reflective layer is too exposed.

Sadly, DVDRs have their own problems despite the “superior” sandwich structure… :bigsmile:


#4

Thanks Francksoy,
I’ve had a couple of CDR,s that the top layer flaked off in a small area and like you said it makes the disk unreadable. I thought this might be the reason for the change in structure.
Thanks again.
wobble


#5

Since, in a DVD, the laser is .6mm closer to the reflective layer than a CD, doesn’t that allow for “higher density” recording, than if the reflective layer were say, 1.2mm from the laser? I think that’s one of the reasons for the new “sandwich structure”.

AFAIK, this is also one of the reasons why BD’s capacity is so much larger than HD DVD’s.


#6

repost, please delete :flower:


#7

LOL, I’ve had pressed CDs where I saw flaking…mind you, this was a loooong time ago, and they were used (played) a fair bit. :slight_smile:


#8

Definitly makes sense. [B]@Wobble[/B]: my input was conjectural. As you can see from Buck’s input, there can be many other sensible reasons for the change of structure. :slight_smile:


#9

Now you just got me thinking again. It hurts when I do that!


#10

Did you mean that some DVDs are prone to splitting or something else?


#11

Well you shouldn’t ask such questions if you don’t want brain pain, that’s why I try to avoid them

That and other things like fast degredation, poor quality control, no control over the so called “grade” of media, just to name af ew.


#12

This happens, indeed, but not really often (fortunately). But repeated bad handling can actually cause mechanical damage to the structure of the disc, without going as far as splitting into two halves. :frowning:

I was mainly thinking of the higher data density, and the related much narrower mechanical tolerances for DVD burning and reading. The slightest warping for example will impact DVD burning/reading, though the same amount of warping will have a very limited impact on CDR. That’s why BTW paper labels can be OK for CDRs but can have a huge negative impact on DVDR redability.

So the “superior” structure is not enough, in my view, to compensate for the much higher mechanical exigences. Thus the countless recommendations to take great care of DVDR, to store them vertically, to avoid warping them when talking them out of their cases, etc… :rolleyes: