Effect of storing BD-R in wallet case

vbimport

#1

I was having trouble reading files stored towards the outside of several CMC BA3 discs. Windows was having real trouble reading the disc at these locations and throwing up lots of ‘bad sector’ errors in event viewer.

This is what the disc scan of one disc looked like:

I planned to perform more scans on affected discs and evaluate how many discs had gone bad etc, but I did not have time so I put the disc aside in a nearby jewel case to keep it handy.

I revisited the disc some days later and noticed something strange. The bad files were verifying just fine now. So I re-scanned it and now it looked like this:


Not an amazing scan and worse than a typical 0-day scans of these discs but still…perfectly readable. This was taken about 5 days after removing the disc from the wallet.

Pretty interesting. It seems that:
1 - Storing the disc in a wallet really screwed up the discs…maybe warped them or imprinted a pattern on the surface. Of course many people say not to store discs in wallets but I did not expect such a dramatic and rapid degredation of the disc.
2 - The disc seems to have ‘fixed’ itself (at least partially) via several days of being stored properly in a jewel case. Maybe something to do with the elasticity of the disc, or the viscosity of the hard-coat?

Anyway I found this pretty interesting. You might think I would never store discs in wallets again but actually I put some more in to see if I can replicate this :smiley:


#2

You aren’t alone: http://club.myce.com/f33/warning-dona-t-stack-blank-bd-r-dl-discs-sleeves-337846/

I think there may be at least one similar thread for BD-R, and probably more that involve CD/DVD (though the effect on those may have been less pronounced).


#3

The sleeves are fine if you keep the binders vertically so there’s little pressure on the discs against the mesh/fabric. If you lay the binders down or worse stack several of them on top of each other the “soft coat” on the bottom of the disc that provides the scratch resistance will take on an impression from the fabric. The good news is that the impression goes away after a day or two after you flip the binders vertical.

CDs and DVDs don’t have a soft coat on the bottom so they seem to be immune to this problem.


#4

[QUOTE=Stereodude;2752081]The sleeves are fine if you keep the binders vertically so there’s little pressure on the discs against the mesh/fabric. If you lay the binders down or worse stack several of them on top of each other the “soft coat” on the bottom of the disc that provides the scratch resistance will take on an impression from the fabric. The good news is that the impression goes away after a day or two after you flip the binders vertical.

CDs and DVDs don’t have a soft coat on the bottom so they seem to be immune to this problem.[/QUOTE]

This particular binder was stored vertically with the spine oriented at the top. The outer cover is stiff/strong so the binder pages were hanging freely from the spine with I think minimal pressure or warping.

Yes, DVD seems less susceptible. There had been DVDs stored in the same binder for even longer and they never showed any problem. I think Bluray with much lower focus error limit (45nm vs 200nm) is inherently more susceptible to surface imperfections.

It might be interesting to perform more experiments and see if I can narrow down the factors that cause it and also how quickly it ‘recovers’.