Talk:Disc rot

Additional merger suggest

There is another article on LaserRot - wouldnt it make even more sense to merge these instead of merging this article into the main CD-article, as the problem obviously applies to more media?

I think should do it

Mention problems with label stickers?

Having trouble finding the reference now, but there is evidence that with CD-R discs that have the metallic recording layer exposed stickers can cause read errors over time. This may be caused by temperature having a different effect on the sticker than on the metallic coating on plastic. -- M0llusk 05:26, 22 December 2005 (UTC)

I have experienced problems with labels on DVD's, although not on CD's. It always starts at the tail end of the DVD and works its way to the beginning. As a rough example: 2 or 3 months after burning a DVD-R and placing a NEATO label on it, it will not play beyond the first half hour. Then after 6 months, symptoms appear after 10 minutes. And some time after that, the entire disk is unplayable. Even my computer can't read it. This has happened on every single DVD I have placed a label on (and I have of course stopped doing that now). There are no visible signs of deterioration on the disk itself, at least not with the naked eye. T. 76.113.109.160 (talk) 07:57, 7 December 2009 (UTC)

Conjecture on why DVD rot is much quicker than CDR rot

If I remember correctly, CDR actually wastes a lot of space in writing stuff in different ordering (stuff like numbers in both little and big endian), while DVDs don't do the same thing, and pack a lot more data to it. I suppose if indeed a lot of duplicate data are stored, you could recover a bit easier than DVDs.

Or, more likely, DVD manufacturers perfected a shorter lifespan to force people to buy the media a second time. This is done via planned obsolescence and the like in many products -- products are intentionally fragile or flimsy not just because of low-budget manufacturing but because of specific choices in the technology or design.

To begin with, this article needs to demystify one of the two arguments that CD rot is a significant problem or CD rot is rare. I poke around and I can see that some websites talk about solutions [1] where other websites deny a problem [2].

So who's right? Should we trust the stories given by the creators or manufacturers of CD/DVD technologies? Their best interest is to reduce the fear of such a problem. Should we trust the people selling solutions? Their best interest is to elevate the fear to sell products. We could trust "independent labs" but it's a safe bet that their findings are bought and paid for. Basically, this article would need to discuss the underlying physics and material sciences to describe how rot could happen, what could cause it and what would help prevent it..

-- Sy / ^(talk) 01:20, 18 January 2007 (UTC)

Other notes:

CDR is Dependant on the stability of the dyes and the reflective layer. DVD rot is likely more to do with glue layer failure (separation or contamination) as it mainly happens on double-layered discs. CD and DVD are different materials as well - DVD is silicon/gold reflective layer and CD is aluminium. Current DVD case design promotes layer failure as it forces consumers to flex the discs each time they are removed.

"When the CD is held up to a strong light, light shines through several pin-prick sized holes. This is especially noticeable in older CDs that have a label of black text and a silver finish."

The above quote is incorrect in context - pinholes are *not a symptom of rot*: they are unevenness in coating during manufacture and remain stable in size and number during the lifetime of the disc. Earlier discs have more of them compared to recent ones.

Nimbus (UK) have released some comprehensive white papers on longevity, faults, and decay modes of CDs and DVDs, which have, for the most part, been ignored in web debates, which are mostly speculation rather than fact (for example, many people still think the silver reflective layer in a DVD is aluminium, not silicon, or think polycarbonate is immune to humidity absorption compared to LD's acrylic discs - less pervious does not mean immune). etc.

Also of note is that different styles of CD are more prone - clear edged and center disks are fully sealed while the old Phillips style (solid center/edge) have cut unsealed edges. Highly recommend getting hold of Nimbus' (UK) white papers, also Pilz who specialise in long life discs. [PEC]

Difference between mastered discs and burned discs, CDs and DVDs

I understand that mastered discs use physical pits, whereas burned discs (CD-Rs, DVD-RW etc) use chemical transformation. I'd expect this to have a difference on the mode and timescale of decay.

As for CDs versus DVDs, I'd imagine that video data is more bit-critical than audio data where bits could be skipped and interpolated more readily by the player?

--Bobacus 14:45, 8 August 2006 (UTC)

Means of circumventing CD rot

It is complete BS to think that storing data on a hard disk means anything. Bits can be dropped at any moment, and making backups just backs-up the damaged bits. Similar issues exist in RAID setups.

Means of true infinitely-lived backups involve keeping very good CRC-type records of every single file as well as CRC-type records of your CRC-type records and doing comparisons before backing up the media.

The section, as it stands in the article, is completely misleading. This is a very complex topic to discuss.. =/

-- Sy / ^(talk) 01:09, 18 January 2007 (UTC)

sorry, i would have to disagree with this strongly, bits of data can be dropped on a hard-drive only if the drive is either faulty or not working to it's full capacity. Those who take care of critical data often scan discs - no errors means that the data blocks and sectors are intact, thus the integrity of the data is fine. Whitewater111 (talk) 02:42, 20 January 2013 (UTC)

various resources

Here are some misc. resources I've bumped into.. add to this list or take a look and see if anything here is worthy of discussing in this article:

• A bad case of DVD rot eats into movie collections
• http://www.dvddemystified.com/dvdfaq.html#1.24
• http://www.audioholics.com/techtips/specsformats/CDDVDlongevity.php
• The National Institute of Standards and Technology - how to care for your disks
  • a preliminary study
• http://www.123sortit.com/sanity/dvd.html
• http://larryjordan.biz/articles/lj_dvd_life.html
• http://www.findarticles.com/p/articles/mi_zdpcm/is_200405/ai_ziff126783

Severe DVD rot (or is it something else?)

Sorry about the glare from the flash but more evenly lit photographs and scans failed to highlight the defects in the disc. I don't know if this is a common example of DVD rot, or whether it's a one-off manufacturing error that causes the outer surface of the disc to 'melt' or time.

This disc is from a 2-disc set of The Terminator manufactured in 2001; the rot was noticed in 2005. Both discs in the set were affected; they were stored in their original box alongside the rest of my collection – they are the only discs that this happened to. The disc will not play and the surface has become sticky to the touch; note the overall 'cloudiness' of the surface and the ring a quarter of the way in.

Note that the smudge in the upper right of the disc is a fingermark. Interestingly, the degradation is more pronounced around the fingermark. The darker patch near the hub and thicker parts of the ring appear to be more rotten.

Danny Darko 19:57, 8 February 2007 (UTC)

This isn't rot, but rather a bad reaction with the inks and/or adhesives used in the special packaging that this Region 2 release came in. The same thing happened with a parallel release of Silence of the Lambs You can see a near-contemporary report here, about a third of the way down the page. Also discussed here, with some people getting acceptable results with proprietory CD cleaner. Just looked at my copy for the first time in about five years and the discs are in need of attention! The odd thing is that the residue is on the discs, but not the plastic parts of the packaging. Nick Cooper 00:57, 1 April 2007 (UTC)

Thanks Nick. --Danny Darko 17:55, 14 April 2007 (UTC)

Play Count

Is there any indication that DVD/CD rot occurs more often (or more rapidly) on disks that have been frequently played, or is a steady, unstoppable process? A lot of CDs I purchase now, I rip directly to my PC and store the discs in a safe place; will this give them a longer life span? PolarisSLBM 18:11, 12 May 2007 (UTC)

Not to my knowledge. The bronzing effect that occurs with audio CDs made by PDO UK is a progressive decay due to a problem in the manufacturing process that seems to occur regardless of how often it has been played -- however, if PDO's first explanation was correct, then removing the CD booklet from the jewel case might have been helpful. From my own experience, the two affected CDs that I have so far found in my collection weren't played more than perhaps 5-10 times each, so I doubt very strongly that there is a connection with the playing frequency.--Hprill 00:44, 2 August 2007 (UTC)

Petition Link...

I took out the link to the petition. I doesn't add anything to the article and seemed more like someone pushing their agenda than anything else. 72.69.129.226 14:37, 25 July 2007 (UTC)

Integrate "DVD rot" issue?

As I read in several comments above, DVDs may be affected by "DVD rot" or "DVD bronzing". The article doesn't mention DVDs at all, and there is no other article on Wikipedia. It would make sense to add the DVD-specific information and rename the article to "CD/DVD rot", or add a separate page. 62.216.211.54 (talk) 22:56, 29 June 2008 (UTC)

Personal experience

In 2003 I bought a Mac (G4) with a (Then very expensive) dvd-Burner installed. I installed a (Very good, Miglia) video & T.V. card in it and, being a film-afficionado, started to make my own private film-collection (Using iMovie and iDVD to edit and burn the DVD's).

And, yes that's illegal, I know.

Having over 25 cable-channels in Belgium and buying regularly new DVD-writers to install in the Mac's second bay (And also an - expensive - LaCie firewire external burner), I soon had me a very nice collection of 1200+ DVD's with films and series (Burned on all formats: DVD+, DVD-, Double-Layer+ and Double-Layer-). Due to a hectic life I seldom had time to watch them but nevertheless noted over time that more and more of the discs became unreadable. When, by 2009, media-players became widely available (And my lifestyle settled), I decided to recode all my discs to the XVID-format of the - far more practical - media-player (Which allowed to attach a second hard-disc to contain all my movies). To my horror, by that time, about one quarter of my self-recorded DVD's had become totally unplayable. That's 25% over a timespan of only six years! (With thus, a medium age of the DVD's of only three years).

These DVD's were not only of all formats but also carefully stored and of many differant brands which showed no significant difference in susceptibillity to 'DVD-rot', except, perhaps, for the SONY's who were the worst!

Hard-disks, having become so cheap and of such increased capacity, are now the sole medium on which I keep all of my media: Films, Home-movies of the kids, photo's and Music (Don't copy your iTunes-library onto DVD's as iTunes wants you to do!). And, since the aforementioned drop in price of external hard discs, I do it in threefold!

Sorry for not signing this contribution: I forgot where to find "Tildes" on an AZERTY Mac-keybord. — Preceding unsigned comment added by 81.243.135.116 (talk) 22:19, 28 October 2011 (UTC)

Incense sticks can destroy discs.

You do not want incense sticks to come in contact with optical discs, even if they're wrapped in plastic. I've seen DVDs destroyed by the oils in the sticks penetrating their plastic wrapper then through the disc's plastic to the reflecting layer. The plastic gets fogged and the reflecting layer gets corroded. Bizzybody (talk) 00:44, 17 July 2016 (UTC)

Fungal Disc Rot

I've seen this a couple times, more info[3] 208.185.199.138 (talk) 23:43, 30 May 2018 (UTC)