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View Full Version : Be warned! "DVD Rot" could be to blame!


TRILIGHT
16th February 2003, 21:58
I came across this article today on www.smh.com.au ...

A bad case of DVD rot eats into movie collections
By Sue Lowe
February 1 2003

If you think your prized collection of DVD movies will last a lifetime, think again - some are already starting to rot while others are falling apart.

Unofficial estimates put the number of affected discs at between one and 10 per cent. Yet some of the largest distributors for Hollywood Studios are accused of refusing to accept the problem exists and replace faulty products.

Last year Australians spent $398 million buying 13.3 million DVD movie titles - a three-fold increase on the 4.3 million sold in 2001, according to research firm GFK.

The technology, sold as a replacement for VHS video tape, with added interactive content, is now five years old and the DVD industry claims it is the most successful packaged media in consumer electronics history.

The failures are a combination of corrosion - known as "DVD rot" - and delamination, where the layers of the disc separate.


Symptoms of the rot include picture break-up and freezing at a specific place on the disk. The main cause is believed to be poorly designed cases. Delamination shows up as a coffee-like stain that prevents the disc from playing.

Among those worst affected are video rental stores, which buy millions of DVDs per year.

"Some stores have reported they only get two or three rentals from a DVD before it's unplayable," said Ross Walden, director of the Australian Video Retailers Association.

Distributors "are washing their hands of it", he said. "Once a DVD has been rented out [distributors] will not take them back."

Rohan Byrnes, 34-year-old science fiction fanatic who owns 350 DVDs, has spent a lot of time looking at rot. He works as a failure analysis engineer, with access to an optical microscope.

Mr Byrnes has studied five cases of DVD rot - four in his own collection - and suspects the microscopic corrosion spots on the aluminium layer inside the disc could be caused by a "chemical attack", possibly related to the glue used.

One DVD website lists 18 titles known to have at least one bad batch, among them Planet of the Apes (1968), Men in Black: Collectors Edition, Independence Day and the Alien Legacy box set.

Mr Byrnes returned his discs to the distributors, 20th Century Fox and Columbia TriStar, enclosing his analysis, and got replacements, but other victims were not so lucky. Peter Longworth, a DVD collector in Newcastle, had an identical problem with Planet of the Apes two years after buying it.

However, 20th Century Fox refused to replace it as it was out of the 90-day warranty.

"The company refused to accept that there was a manufacturing problem," he said. Mr Longworth wrote to the Australian Competition and Consumer Commission in November, but the watchdog does not act on consumer warranty issues.

Meanwhile, 20th Century Fox declined to comment on the matter. A spokesman said only: "We always fully compensate our customers for any manufacturing fault found." Warner Home Video's managing director, Stephen Nickerson, said: "If a customer has a problem with a disc and it is clearly a manufacturing problem we will replace it. The question is whether it is caused by a manufacturing problem or customer abuse."

Nic
16th February 2003, 22:25
http://forum.doom9.org/showthread.php?s=&threadid=44684 ;)

hype or truth...ill believe it when I see it :)

-Nic

midiguy
16th February 2003, 22:26
ahhhhh this again! you can find many articles talking about "DVD rot" but I want YOU to try finding someone with a DVD that has "rotted". sounds like a myth to me (there was a myth many years back about "CD rot"). I won't beleive it until I can see it first hand.

TRILIGHT
16th February 2003, 22:55
Well, the reason I thought it was so interesting is that my brand new spindle of blanks I have sitting here have exactly this type of "coffee stain" effect in the center ring! The first I've seen like this. Granted, it only seems to be contained to the center ring but I can't help but feel as if this may eventually become a problem for me down the road when these discs have already been burned and have sat around for a while.

mpucoder
16th February 2003, 23:43
Let's be clear whether we're talking about stamped disks (both CD And DVD) or recordable disks. The article is talking about stamped disks, and I have yet to see a problem with them. But I have seen firsthand problems with CD-R (generic from CompUSA) and CD-RW (Princo). These disks had problems with the dye fading, not delamination. I've seen delamination on LD, which is probably where this urban myth originates.
But I still cringe when I have to pry a DVD out of its case - that's got to be tough on the disk.

TRILIGHT
16th February 2003, 23:50
Ok, let me specify then. I've never seen it on anything except the spindle of DVDR blanks I now have. When I came across this article today, it described the "coffee stain" effect I noticed perfectly. I would have posted this article in the DVD Authoring forums since I figured others should be on the lookout for potential problems with their DVDR media. I certainly didn't expect to take a bunch of CRAP from everyone by posting in what I thought to be the more appropriate "general discussion" area.

markrb
17th February 2003, 01:08
I have seen this on laserdiscs. It was a fairly common problem with older discs. I have several that have laser rot. It comes from exposure to air, either during the manufacturing process or after.
You can literally see crystals forming inside the plastic.

Mark

jggimi
17th February 2003, 02:46
Delamination shows up as a coffee-like stain that prevents the disc from playing..Delamination would only effect dual-layer discs. Burnables are single layer, so this shouldn't apply.

TRILIGHT
17th February 2003, 06:08
Why do I have this "coffee stain" effect in the center ring of these blanks I have?

waldok
17th February 2003, 13:41
...because you shouldn't use your DVD-Rs as saucers for your "late- night uberguide-writing coffee-sessions" :D

Seriously, I have the same effect on a few DVD-Rs from a spindle (BulkPaq DVDRs). They burn fine though.


Waldok:cool:

mikeathome
18th February 2003, 13:57
Hi,

I am not fully sure whether I understood you right. If you mean a small ring just at the inside of the DVD-R then there is a simple explanation:

DVD-R for General have a 'pre-burned' area on the disc where usually the CSS keys are stored. This ring can be more or less visible when looking onto the burning layer side of the disc. The area needs to be 'pre-burned' for Video-DVD compliance.

mike

Richard Iredale
18th February 2003, 17:37
The DVD-R disks I have are made by laminating two thin plastic disks together, with presumably the dye sandwiched in-between. You can always tell a DVD disk from a CD by looking at the spindle hole. On a CD, the edge of that hole clearly shows as a single piece; on a DVD, the edge clearly shows that the disk is a sandwich of two disks.

Recently when I attached some labels incorrectly to a couple of burned DVD-R disks, I used WD40 to remove them, then washed the disks multiple times in warm water and soap to remove the WD40 residue. I noticed afterwards that soap bubbles were left behind in the center spindle area--implying that there is no adhesive in that area, but rather a very small air gap. Perhaps what you are seeing is just some "crud" that got into that air gap during manufacture. I personally wouldn't worry about it.

BTW the WD40 technique mentioned above works great. Just remember to never rub the disk with anything other than your fingers or a clean washed cotton shirt. The disk will play fine with scratches caused by paper towels, etc., but it looks like hell. And, of course, there is no way of hurting the data layer. Unlike a CD, the data is in the middle of the sandwich, not on top.

TRILIGHT
18th February 2003, 17:38
Nah, I know what you're referring to, Mike. This is a non-uniform deformity in the center ring. Almost looks as if there is water trapped between two sandwiched pieces of plastic.

mikeathome
19th February 2003, 09:19
Originally posted by TRILIGHT
Nah, I know what you're referring to, Mike. This is a non-uniform deformity in the center ring. Almost looks as if there is water trapped between two sandwiched pieces of plastic.

Ah, ok, I do understand.
I've never seen such 'marks' on the Verbatim/Apple/Pioneer I use ;-).

mike