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Originally Posted by Superstar**
Hi, I have a really stupid question for you lol..and I feel really stupid asking you this..and I'm sure you'll think I'm really stupid after you read this..but..here goes. I know there's markers that are made exclusively for writing on CDs/DVDs...however, I bought a Sharpie marker today to write on the front of my DVDs...will that do any damage to the DVDs at all? Is it ok to use?
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In the pre-Internet world, yes, this probably would have been a stupid question. While the current times are often referred to as the "Age of Information" due to vast technological advances in communication (the Internet, mobile devices, worldwide fiber networks, etc), it's also the Age of Misinformation. Myths, propaganda and straight-up bullplop spread quickly online. So it's sadly quite easy to become confused or unsure of yourself, when presented with so much baloney online. And that extends well into video and media products. You get a free pass on this one -- it's not your fault that you're asking a stupid question.
Let's start with a DVD...
A Sharpie marker will not damage a DVD, no. It's physically and scientifically impossible. Think back to the physical structure of a standard recordable DVD:
| Label and lacquer layers
| Upper polycarbonate layer
| Foil layer
| Dye layer
| Lower polycarbonate layer
For the sake of being mentioned, note that: (1) Pressed/replicated DVDs lack the dye layer. (2) Burner double-layer (or dual-layer) discs have an added dye layer plus a dye layer spacer. (3) Rewriteable discs like DVD-R, DVD+RW and DVD-RAM lack a dye, but instead use phase-changing crystalline structure alloys at the same layer location. --- Not that any of this is really germane to the conversation, but I want to be sure every aspect is fully addressed. Let's fully 100% dispel this myth here.
The important piece of this puzzle is that upper polycarbonate. It's a very dense and transparent plastic polymer. Note the "carbon" in the polycarbonate. Carbon is a very dense and durable material. Ever hear of carbon fiber? It's stronger than steel, thanks to the carbon.
The myth used to sell "DVD safe" markers is that so-called "acids" will eat through the disc. This is false. In fact, it's so false as to be ridiculous, and should be mocked for its stupidity. Sharpie pens would have to be very toxic and have a high concentration of lethal acids, in order to cause that sort of destruction to a DVD. Of course, such a nasty cocktail would also fair poorly as a writing utensil, so it would be difficult to call such an acid stick a "pen" (or marker). It would not really be able to write.
The weakest part of a DVD is the binders (or glues) that hold the polycarbonates together, forming your DVD layer sandwich. I guess in theory, if you coated the edge of a disc in standard non-AF (acid free) ink, you could accelerate aging and cause decay. It would not be immediate, however -- none of that ridiculous "6 months" type paranoid rambling you may have read in forums or on blogs. (Notice that all such non-sense tends to generate from lower-knowledge users. Although it's worth mentioning that some of this ridiculousness has leeched into the archival sector, and those who would parrot it lack proper knowledge to know otherwise.)
Now let's look a CD...
A CD could potentially suffer damage from so-called "acids" in markers, but it's still unlikely. Again, we need to consider the structure of the disc in question:
| Lacquer and/or labeling layer
| Foil layer
| Dye layer
| Lower polycarbonate, which actually creates the bulk of the thickness of a CD
To actually cause major harm to the disc, acid would have to first eat through the lacquers, which is certainly quite plausible. Next it would need to attack the sputtered foil layer, which is where the myth of "acid eating a CD" falls apart. The sputtered foil layers are a mix of primarily gold or silver, with a few other alloys to fortify it, and it would take a pretty potent cocktail to eat through gold or silver. Again, you'd have to use a lethal acid stick -- not a writing pool with trace amounts of acid in the writing ink.
A CD does not have bonding agents like DVD, so writing on the edge of the disc won't have any effect.
The easiest way to "fight" this is to write on a CD with a branded or inkjet writing surface -- don't write on the mirror "shiny silver" part of a disc, as that's nothing more than lacquer on foil. Keep the writing off the lacquer, and you should be fine. The label areas are there for a reason. If your discs lack a writing area, then write in the hub. Or use a hub label. Note that full-face CD labels are not suggested, as it tends to throw off the balance of the disc over time. (There's also the issue of sticky label glues eating at the lacquer layer!)
Can acid eat a disc?
In fact, the only way you can easily screw up a disc, by using an acid, is to subject it to something where acetone is present, as acetone eats plastic. Or in this case, destroys the polymer.
Why does this myth exist?
This is all due to weak extrapolation based on various papers, such as photo paper, and how long-term exposure to certain inks/acids will ruin paper over time. Acid-free plastic storage, acid-free reinforments (comics backing board, for example), and acid-free pens are very important to long-term viability of papers. Even the papers themselves can have too high of an acid content to have long-term shelf life. Photo paper is especially succeptible, because it's chemically active, and further chemical reactions happen over time. It's why photos turn yellow or brown over time, and why writing can bleed through from the reverse side. Not inkjet photo paper, but photographic lab paper.
Discs are essentially a continuation of both traditional print storage and computer magnetic discs. Paper users were concerned about acidity, and acid-free "safe" products sold well. Since those same people are involved in modern media use, the old concerns of acidity still exist. Therefore the market exists, because the product was demanded.
Nevermind that it's something that exists solely because people are stupid enough to buy it.
Sharpie has already fully investigated the concerns resolving Sharpie branded markers (and several competitor markers, from what I recall), and came up with the scientifically-likely conclusions that it was all bollocks. There's no truth to acid in markers "eating" your CDs or DVDs. At one point, I saw their white paper on this, and I may have even saved a copy, but it's not within easy reach at this moment.
Another issue is that the inks would fade over time, and may even change tint (yellow faded writing instead of black, for example), which many mistook for some sort of damage. It's simply an issue of the inks not really being permanent, as propanol is a major ingredient. (Yes, that brings up the misleading idea of a "permanent marker", but that's another conversation entirely.)
Is it safe to write on a CD or DVD with a Sharpie marker? Yes, it is! 
Hopefully we'll save you from wasting money on those "safe" markers. Note to mention Sharpie has so many choices in colors and tip styles!
I suggest the Extra Fine tipped markers:
http://www.amazon.com/gp/redirect.ht...reative=390957
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