Why is CD underside more durable than the same on DVD+-R

[jtoolman2000]

Yesterday I gave a friend at work a blank CD-R that she ended up not using. She promptly returned it but not before planting a couple of nice fat fingerprints on the underside surface. I used my T-Shirt Sleeve!!!!!! to wipe the offending prints off and not a simgle scratch was created on the disk.
Now If I was to do that on any of my DVD-R disks, the figerprint would be promptly replaced by hundred pretty little scratch marks. You would think I rubbed it with pumice. Even my smooth clean finger tips if rubbed un the underside of a pristine DVD-R will easily scratch the under surface of the disk. The same does not occur on CDs
I had heard of a so called "Tougher" disk being sold. I forget the name but it claimed that it would resist most common abrassions. I don't know the diference in the plastic used on CDs and DVDs or their composition and I simply could care less. My question is why can't the DVD-+R industry use a better material such as that used on even the cheapest CD-Rs. I mean these things are so damn fragile they even arrive scratched just from sitting on the spindle rubbing against each other in transit.

[samijubal]

Use Plexus and a soft cloth. If it leaves any scratches they are very minor. I use it on all rental discs before playing too. You can buy it in motorcycle shops for about $8, works excellent.

[jtoolman2000]

I am not really concerned about how to prevent scratches. I know how to do that. I am asking why CDs are made of a lot more durable plastic than DVD-Rs
There is a huge diference in the actual plastic used for both. Under the same mistreatment, the under sides of CDrs are more durable and a lot less abrassion prone than DVD-Rs.

I am simply wishing they would be made of the same material or al leat more durable.

[chas0039]

My guess would be that it is because the CDs are made from a single piece of plastic that is thicker and the DVDs are made from two lighter pieces of plastic sandwiched together. This is the only difference I can think of that would limit the manufacturer's ability to do what you want.

[Skith]

It is also possible that the particular DVD was manufactured poorly. It could also be that the material used is different, since DVDs require a different wavelength of light (much narrower). Another possibility is the different dye color causes the scratches to be more visable.

These are only guesses though.

I am sure you already know this, but I will state it for those that do not: Wipe with a soft lint free cloth, such as those used to clean camera lenses. Start at the center by the hub and wipe from center to edge. Avoid circular motions!

For those who are clumsy, check out TDK's Durabis (I think I spelled that right) formerly known as Armor Plated Discs. It takes quite a bit to scratch these. (I have used a few older 2x DVD-R TDK armor plated discs). They are not cheap though.

[lordsmurf]

I don't necessarily agree that CD is more durable than DVD on the write side.

[lumis]

correct me if i'm wrong, but isnt the error correction on dvd's much greater than cd's? and isnt large portion of the data on a disc devoted to error protection?

i'm remembering this from a long time ago, so i could definetly be way off..

[jtoolman2000]

I just did this. I took a blank CD-r and rubbed the underside with my finger tip for ten sencond. Results: Smudges but no scratches. Did the same thing to a blank DVD-R ( TKK ) Result, Smudge and lots of little scratched in the direection of the rub. Cunclussion, the PLASTIC composition is more susseptable to scratches than the plastic on CD-Rs

That's why there are "Armor Plate" disk being offered.

Commercial/Pressed DVD also seem a lot more durable. Are they Polycarbonate as oposed to cheaper styrene for the +-R type? If I take a brand new store bought DVD and wipe the back with clean lint free cloth, I get 0 scratches. DO the same to a DVD-R and BAM, lot of scratches.

I am not trying to start anything but it really getting is anowing to have to super baby these disks. as I produce them by the hundreds in my business. I will CULL out a disk for ANY mark or abrassion I find after I burn and print them. I am pulling out about 5% and tossing them. They would problaby play and scan with no problems but I cannot take a chance at all.

[Jester700]

That's interesting. I'd like to see a wider ranging test - more blank brands and maybe a more "calibrated" procedure.

IIRC, DVD production came from CD production, and the less change in materials and tooling, the easier the conversion to DVD production. It doesn't make sense that they'd use a different material than CD's polycarbonate. Particularly one with lesser characteristics - especially considering the tighter read tolerances and the associated greater effect any scratches could have.

[yoda313]

Hello,

Also - the DVD has much smaller pits and grooves to store data. That's why it's capacity is so much larger than a cdrom.

Perhaps its this density that is part of the problem - as well as possible cheap manufacturing as mentioned earlier.....

Kevin

--boy how bad would a scratch on a hd or bluray disc be???? ---

[lumis]

probably not too bad, because they'll have an even higher level of error correction

[samijubal]

Part of it is that it's easier to see scratches on DVDs because of the darker dye. CD dye is alot lighter and doesn't show scratches like the darker DVDs. They may be just as scratched, you just can't see it.

[jtoolman2000]

Forget about whether the data can be read or not. I am talking about the PLASTIC being used. IT IS DIFFERENT. I don't meant to shout but I don't think my point is getting accross. If they were two plain disks with nothing in them, no dye no nothing, The CD is LESS prone to scratching that the one designated as the DVD. Pressed disks are alsom made of a difeferent material, matrix or whatever you want to call it. I would pay a buck a disk just for the extra abrassion protection better toughgher plastic would provide. As they are now even my finger tip will make scratches on DVD-Rs. I have some dark blue CD-Rs as well so it's not the fact I can't see due to one having light dye and the other dark.
Try it, you'll see it even feels diferent.

[ice-berg]

jtoolman2000 the best way to know is to scratch the dark blue dye cd and a dvd with the same aritifical scratch, then observe.
if you are willing to pay the extra buck, you could alawys get the TDK armor plated discs (they claim to be 100 times more scratch resistant).

[lordsmurf]

I agree. Babying discs is getting annoying. But I think VHS was the same, somewhat. Had to be careful of eaten tapes, etc. I hated that too

Dark dye vs light dye. Good catch! I notice my blue-dye discs have just as many scratches as a DVD does. In fact, all I use are dark dye discs. I never liked the green/silver ones, as the CD lasers in various players I have would never pick up on them very well.

Armor plated work well.

[yoda313]

Hello,

Had to be careful of eaten tapes, etc. I hated that too

{shudders}

Ugh... I HATE THAT as well.... Especially if there were some special episodes you wanted to keep. Yuck.

Kevin

[koolaidwa]

i have some dvd media that wont sctrach unless u sctrach it with something hard, i find that dvd are more durable then cd's

[Captain315]

If you've discovered a new type disk, let us all know. I agree that these DVD's are entirely too fragile for even storage. Wish I could find something that would coat the disk and protect it from normal handling. There's got to be something out there that will work.

[samijubal]

Use Plexus, it's made to coat and resist scratches. It's actually for motorcycle helmets, but works excellent on discs.

[lumis]

it would be nice if drive makers let us have the option of using disc caddies (condom). even though i take good care of my dvd-rw's (for recording on standalone and transferring to PC) they do get scratchedup during normal usage after a while.. i'm not saying that disc makers should provide us with caddies, just give us the option to use them. then again, dvd-rw's really dont cost THAT much.

[Stormin Norman]

It all depends on the plastic used in the injection mold/vacuum forming/thermoforming process. Each manufacturer has there own specs on type of plastics/process used. More than likely its a type of acrylic. But a plastic can be altered very easily by adding another type of plastic or chemical to alter its characteristics: tensile strengths, durometers, hardness, molecular weights, coatings, stiffness ect.

[cyflyer]

jtoolman2000 does have a very valid and interesting point though. The material they use in the TDK armour plated jobs, should really be the 'standard' material. I guess though it all boils down to one thing as usual. PROFITS ! Lots of godamn profits. With the advent of standalone DVD recorders and computers with DVD burners, there are probably more dvd media to sell than there were cd-r's. Make 'em cheap as possible from the durability point of veiw, sell more, make lots more money. Yes, they can make them more durable, if they wanted. In the end, we are the suckers.

[vitualis]

I am pretty sure that the base substrate for both CDs and DVDs is polycarbonate.

The TDK armour coated discs have an additional coating that makes it resistant to scratching.

Regards.

[waheed]

as far as i know, dvd is half in thickness than a cd

[cyflyer]

as far as i know, dvd is half in thickness than a cd

dunno about that. U got my curiosity going and I rushed over for my verniers, a cd and dvd. Seem the same to me, about 1.25mm.

[jtoolman2000]

jtoolman2000 does have a very valid and interesting point though. The material they use in the TDK armour plated jobs, should really be the 'standard' material. I guess though it all boils down to one thing as usual. PROFITS ! Lots of godamn profits. With the advent of standalone DVD recorders and computers with DVD burners, there are probably more dvd media to sell than there were cd-r's. Make 'em cheap as possible from the durability point of veiw, sell more, make lots more money. Yes, they can make them more durable, if they wanted. In the end, we are the suckers.

That's it!!!!!

I tell you, i have been doing the occassional personal backup for a few year but the bulk of my work has been in high volule duplication to DVD-R from "Disk" images held in internal HDs of DVD duplicators ( produce and sell instruction videos for various hobbies ). I will burn up to 9 disks at a time in one tower. If I even just drag the finished disk or even an unburned disk against anything as I load and un load, I just toss it due to a scratch. It is so bad that even storing the burned and printed disk on either good jewel boxes or DVD boxes will guarantee that they will scratch even with the slightest handling. Of course, I know that minor scratches may of may not affect playback by the customer but I CAN NOT hand over a disk with even the slightest physical fault on them. I know I would not want to recieve a scratched disk myself either.

I'ts all money and our own fault as well as we continually demand lower and lower prices.

What I would like to see is a matrix composed of the same material Pressed disk are made of. Whatever that is. I don't really know. I have over 300 original dvds that are still pristine and that's after several years of "Normal" use. I can not say the same for any of my backups. The backup shows many minor defects from day to day handling where the same conditions do not cause any damage to a real pressed DVD.
WHY??? Because the material is a hell of a lot more durable.

So what it is the bottom line? I literally have to tell my customers to treat their disks with extreme care and I tell them to expect ultimate damage to the underside as they use them. So what good is it to have dyes that last 10+ years when the disk will become unreadable to to physical damage.l

Very sad!

[chas0039]

as far as i know, dvd is half in thickness than a cd

dunno about that. U got my curiosity going and I rushed over for my verniers, a cd and dvd. Seem the same to me, about 1.25mm.

And since the DVD is made of two layers of plastic, the two layers are slightly over half the size. Many of my DVDs are thicker than CDs, just stack up 50 or so and compare the size of the stack. The differences are small but they add up.

[vitualis]

Ordinary CDs and DVDs use polycarbonate as the substrate. So do CD-R and DVD-R.

The write surface of a DVD is "half" the thickness as the data layer of a DVD is "mid-way" through the platter while on a CD, it is immediately under the top surface (which is why a scratch to the top surface of a CD will kill it).

That, however, should be irrelevant as a scratch that is deep enough to penetrate anywhere close to half the thickness of the disc would render it unreadable.

My personal experience is that DVDs (and DVD+/-R discs) are no less or more durable than CDs (and CD-R discs).

Regards.

[blinky88]

jtoolman: You are absolutely spot-on, CD blank media are more durable than DVD blank media, regardless of the some opinions expressed in this post. The slightest mark, fingerprint or the like can make a back-up unplayable, they are extremely fragile. I have never experienced this with CD media. Most responses to your question have been negative, it would seem no-one has any idea .... there are many who simply delude themselves into thinking there is no difference.

I guess, to really get an answer, we need some-one working in a blank media plant to provide the information.

[brokenback]

maybe the refelective surface of DVDs is more reflective than CDs and shows up scratches more easily?

Think about it. Ever looked at your reflection in a CD or DVD? Why is the DVD reflection a better quality?

The dye? The dye for DVDs is made to reflect a plot of very close spirals, closer than CD spirals? Thus it is a better "Plane mirror reflector" than the "CD" reflection???

Maybe??