My distain for Ritek media is no secret, but this morning I noticed something else on those previous backups I did last year, I had never noticed before. Whilst running my finger around the outer rim of the Riteks, they have "dimples", serated edge, like a circular saw. Whats more, they are irregular in spacing, and when veiwing the dye side under strong light, there is a "stress line" radiating towards each dimple. Weird !
I checked all my Riteks, and some Maxells (Ritek G04's), and they are all the same. Some have just a few dimples on one place. Its like they were punched out with a blunt instrument.
Anyone else noticed this ? Check your discs.
These "dimples" on the outer rim would surely throw the dvd out of balance, could these dimples be the source of the infamous Ritek problems ?
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I always thought it was the glue seeping out a bit that keeps the two layers in contact.
This is nothing new, alot of media has similar edges. They 'surely' don't throw my Ritek discs out of balance nor any of my other media with 'rough' edges, I haven't had problems with Ritek media or other media with similar edges. In fact most of the best media I've used has rough edges, including RICOHJPNR01 discs. In contrast, some of the most problematic discs I've ever used, Princo and Optodisc, have smooth edges.
So no, your theory doesn't hold water.
It's glue and plastics.
The only media that I know of that have clean edges are MITSUBISHI and PRODISC media. Just better equipment making the discs.
Yeah guys, but here we have all read the reports of labels slightly off centre throwing discs out of balance, so how can irregular/random blobs of plastic on the very rim, the most vunerable place, NOT cause such problems ?
And incidentally, I have only seen this on my Riteks, not on any other brand.
labels slightly off centre throwing discs out of balance...
I once cut half a label off, creating the worst possible balance problem. The disk was still readable but I thought my DVD player was going to explode from the vibrations!
Paper labels expand/shrink under influence of temperature/humidity changes differently than the disk plastics and then slightly warp the disk. That would lead to laser focussing problems.
Retail pressed discs have alot more balance problems than DVD-R discs. Some of the retail discs I put in the computer drive make a loud buzzing noise from the disc being unbalanced, sounds like the drive is shaking itself to death. I've never heard a sound from any DVD-R disc.
Interesting that anyone would mention the rough glue edges on some media. I found this to be somewhat of an issue with two Toshiba standalone recorders I tried. It rejected 90% of all media I tried including Taiyo Yudens. It was able to load and burn several previously rejected disks after I smooth the edges with a file. Needless to say, I returned both Toshibas and am now happy with my Pioneer.
There seems to be an extreme reluctance by many to accept a fact. Sure, out of balance discs are not good - they don't help improve anything but the endless and very wrong theory that many of our self proclaimed "experts" pontificate about is not correct. The most blathered about subject on this forum is labels. Many otherwise knowledgeable members have deified themselves and rant and snort about "out of balance labels." Their expertise in encoding apps, frame rate, color shifting - - - yudda, yudda , yudda does not make them right on this subject. The "balance" crowd is flat wrong on their diagnosis of the cause of label problems. Just because someone is a master pilot does not make him or her an expert metallurgist on the metal used to fabricate the wing on the plane they fly. For them to pretend to be because their ego drives them to be the omniscient "expert" can even be very dangerous if their self-proclaimed "vast knowledge" causes them to make a misjudgment that puts their plane at risk.
The disastrous problem that labels cause is NOT a balance problem. It is a warping of the disc caused by the shrinkage of the label when the label heats up and is also subjected to changes in humidity. This causes the label to shrink and pull the outer edge of the disc up, which causes a focus problem. DVD players are extremely sensitive to this. The focal length on DVD players is much shorter and much more critical on DVD players than on CDR players. This is evidenced by the fact that it is necessary to put the recording and reflective layer in the center of the disc sandwiched between two thinner disc platters. This places the reflective layer closer to the laser. The slightest variation in this distance such as when a label contracts and pulls the outer edge of the media upward is a serious problem.
Some of these bozos may know all about DVD Shrink but they are clueless about label shrink.
Originally Posted by SCDVD
Imbalance of paper labels creates a HORIZONTAL resulting centrifugal force on the axis of the drive. That probably will reduce the drive bearing's lifetime, but will not lead to a significant excentricity of the rotation, because the disk axis centers the disk (and fixes it horizontally). If that would not be the case, then playback problems would exist everytime also on the inner side of the disk, at the beginning of the movie. But all reports say, that often playback problems are only on the outer side, towards the end of the movie.
Warping creates a VERTICAL effect. It seems to be logical, that focussing problems occur, if the distance between dye and laser optics changes periodically with every rotation. The biggest amplitude of this effect is on the outer side of the disk. That is consistent to reports, that the biggest playability problems are on the outer side of the disk, too.
It is possible to have problems with almost any brand and any supplier. Just carefully inspect the product before using it. Here are some samples.
ESA brand dvd-r, 8X disk, id's as CMC. Delamination is occuring at the lower edge as the fresnel lines show.
Taiyo Yuden, dvd-r, 4X disk. This problem looks like a chemical etched the surface of the disk at the lower edge. You can feel the roughness with your finger.
Originally Posted by lordsmurf
Originally Posted by SCDVD
Although seriously this is one of those things where even your average person can approach the problem scientifically and figure out a few things, just by observation. I'm not expert on anything but I do like to pay attention and my experience with paper labels on DVDs has been the following:
1) Put paper label on.
2) Play DVD.
3) DVD always plays well at the start of the disc.
4) Errors (skipping, stuttering, total lock-up) only appear after a few minutes, and only on later parts of disc.
5) Eject disc, let cool several minutes, try again.
6) Disc plays fine to start.
7) Immediately fast-forward to sections that locked-up before
8) DVD will play sections okay -- for a few minutes
9) Then disc starts freaking out again.
Based just on observation, I realized this wasn't a simple problem of disc balance or the effect should be observable on all parts of the disc, not just certain areas. So why certain areas, and only after time? Again, observation indicates that with time comes heat, and a hotter disc has more errors. Also the errors are later in the disc, which corresponds to further from the center of the DVD.
So what could cause this? Experimentally, I then theorized that with different expansion rates of plastic vs. paper, the disc was "bending" in some dimension due to the paper forcing the disc to deflect as the temperature changed. This fit my theory because deflection would be most severe the farther from the center of this disc you get, as the total effect would be amplified by the paper over a longer lever arm.
Thus, armed with this theory, I removed the disc label (it peeled off rather easily from a warm disc), put the DVD back in the drive, pressed "Play," and voila, the disc played through the end. Huzzah!
Not that this proves my theory about why the label was the cause of the problem. And, quite honestly, it really doesn't matter the reasons behind the facts -- all you need to know is:
1) Put label on disc, experience errors in playback.
2) Remove label, disc plays back fine.
That was all I really needed to know!
Well said Ezemango. You have earned the title of Lord Ezemango. But in order to use it, you will need to develop an obnoxious attitude to go with it. Your previous post was entirely too polite.
OZY, nicely put. That has been my experience as well. Yes, in this scenario you've bonded two dissimilar materials. Change the temperature and... remember your physics classes and expansion/contraction? How about the principle of the thermostat? Unequal expansion/contraction. So the disc is no longer perfectly flat. Anyway, whatever the cause, I have found empirically that labels are a bad idea. But hey all you label lovers, go right ahead.Pull! Bang! Darn!
Originally Posted by lordsmurf
With WARPING I mean, that a "properly" labeled disk warps itself under influence of temperature and humidity changes. The "center of gravity" is still exactly in the middle of the disk.
So imbalance and warping, as defined above, are two different things.
The real problem for playback is the warping, see in the above posts.
The statement "Applying DVD labels not properly centered causes the playback problems", that you read/hear from many people, is a widespread MYTH.
You will get the same playback problems, if they are centered exactly.
I hate to agree with smurfie, but if you think closer about it he got a point in there somewhere. I realized something was wrong when i read what joeg04 wrote: "You will get the same playback problems, if they are centered exactly". You need to consider it closer and hopefully you get the same conclusion as me: If the label is PERFECT centered the force from the shrinking label is working in an almost perfect 180 degree angle and exactly the same force inwards, and exactly towards the center of the disk, all the way around the rim of the disk, the disk will then NOT warp. If however the label is off center the force is not pulling to the exact center of the disk, so if the label now start shrinking it will pull more on some parts of the disk causing the disk to bend up a little in one place and not in others and that causes some kind of imbalance. Ofcourse, the reading problem is still the focus problem, but theoretically (in my theory) it shouldnt occur if the label is perfectly centered. However i guess the ink used on the labels can affect the thermal properties of the label, for example if one half is black and the other white, i then find it very likely that those two halves has different levels of shrinking, so most likely could also a perfectly centered label cause problems in many cases.
Its only a theory i have so far, i might have left out some important factors, hope someone can enlighten it for me in that case.
And: I hope more people will start using printable DVDs so they will drop in price and we will have forgotten about all the "label screwup" threads in no time.
Originally Posted by thor300
...to bend up a little in one place and not in others and that causes some kind of imbalance.
I hope more people will start using printable DVDs
I prefer disks, that are built almost symmetrically between top and bottom side, without an extra labelling layer on top.
Good point you got there, "The slightest asymmetry in material properties will allow warping", but i think a disk is much too stiff. Its like making a bowl out of a round piece of metal, the metal itself can easily be bent, but to bend it equally all the way around the edge requires enourmos force even when the thickness is only 1.5mm. There is a good reason why iron craft companies use excentric presses with up to 100 tonns of stroke power to shape thin metal that you can bend with your fingers. If you want to shape plating with the least amount of force possible you cut slots with equal distance all the way around to allow for approximately equal bending, and i have yet to see DVDs with slots, LoL.
Thats the practical side of it as i see it Forgot to mention i never experienced problems (yet) with labeled DVDs, some of them are more than 1 year old. They play just as good or bad, with or without labels, in my player and the Xbox. They are not so well centered, just cheap and a bit lowres, could be bad glue ). Ill try to sniff them next time before putting them on the DVDs, if i dont get high the glue sux.
Paper labels do not apply enough force to warp the plastic platters of a disc. The paper fibers would shred within seconds, maybe minutes.
A warped disc cannot balance. While you can classify every kind of imbalance possible, it is pointless. Same overall situation ... IT DOESN'T SPIN PERFECT!
The globs of glue, since the are on the edge, and tpyically fairly distributed, it doesn't cause much difference. The outward force is not as affected, as compared to a label or plastic warping (or out of round wobble), which is a vertical issue.
Beside that, warped discs are the product of either (1) improper storage for extended periods or (2) factory flawed media.
I can't help thinking there's an inconsistency in your argument. How, praytell, can STORAGE warp discs, and a label cannot? Have any of you people ever held a disc around the edges and pushed the center? Not all that stiff, is it? Rather flexible, actually. Does anyone know just what the tolerances are for the laser to be in focus? What are we talking, microns?
Oh, and BTW, paper is much stronger than you seem to think. It's nothing more than oriented cellulose fiber, but properly tensioned it's what gives drywall its strength. The gypsum in between has almost no strength at all. Medium density fiberboard relies on a paper veneer for its stability. Paper is particularly strong in tension (if dry). Concrete, on the other hand is strong, right? Under compression it is, but not under tension, it isn't. That's why it needs steel reinforcement, and if it is not pre-stressed, you must deliberately inscribe joint lines to make it crack where you want it to. To assess the strength of a material and its suitability for a particular use, you need to know direction and plane of the force to be applied.
I could adduce further examples but to tell the truth, the subject is boring. With all due respect, your notions on the properties of paper, glue and polycarbonate are mistaken.Pull! Bang! Darn!
Originally Posted by fritzi93
I took a DVD-R with a very good centered paper label applied, that has playback problems. I layed it with the label side down on a ruler. It was flat.
Then I heated up the side of the disk, that is normally read by the laser optics, using a 1800 W hair dryer, for 10 seconds from a distance of 3 cm. I checked again with the ruler: The disk was now warped. The center of the disk was about 1 mm away from the ruler.
I repeated this test with a silver-top DVD-R with no paper label applied. No warping after heating up.
With the heating up I wanted to simulate the higher temperature in a DVD player.
CONCLUSION: The playback problem is warping, not imbalance.
Originally Posted by joeg04
It is also true that this effect occurs to a lesser degree with printable DVD media. The printable surface also contracts when heated and bows the disc up. It is not as much as with paper labels but there is still some reduction in player performance with printable media.
Originally Posted by steve2713
The Princo disk has an extra almost white plastic layer on top (not printable, with blue text on it). That layer seems to warp the disk under influence of heat.
I think that some Princo disks, some white printable disks, and many paper labeled disks have all the same warping problem.
Originally Posted by fritzi93
I've lost discs this way. I knew the day I put the discs in the cases that the slot was warped. I figured "oh well, it'll be okay, surely they wouldn't make something bad". I was new and stupid, and years later, that's the outcome. Luckily, all of that can be replaced. A close friend is in the same situation, slowly swapping out to new cases.
Discs have long had saw-toothed edges. No effect.
Labels do not have the ability to warp a disc. It's simply an imbalance, causing it to wobble off the flat plane. Those cannot be burned or read that way. It's the outer edge that is worst, which is why some labels close to the hub are fine. After time, the thin paper would rip apart, not cause warping. We are, after all, talking about the same paper that pretty much dissolves with a drop of water.
Originally Posted by lordsmurf
Originally Posted by lordsmurf