Why Are DVD-R Discs Purple?
Have you ever wondered why store bought DVD movies are silver on the bottom while the ones you burn yourself are purple? Why is it that DVD-R discs only come in purple but CD-R discs come in a variety of colors? Well, I’m going to do my best to explain the answers to these questions for you.
The reason why retail DVD movies and games are silver on the bottom is because they are produced in an entirely different way than the DVD-R discs you can record at home on your computer or DVD recorder. A store bought disc is produced through a process called replication.
In this process, the information is stamped on to a metalized dye layer from a “glass master” disc. The dye layer is then sandwiched between two paper-thin pieces of high strength polycarbonate for protection. The silver color of a DVD is the result of this reflective dye layer being seen through the polycarbonate.
In addition to protecting the dye layer, the two pieces of polycarbonate plastic give the DVD disc its thickness. This extremely dense plastic material also helps protect the disc from getting scratched, which makes it ideal for retail DVD movies, video games, and other frequently-used media.
However, the expense of producing a replicated disc can only be absorbed by producing discs in very high quantities such as tens of thousands of pieces. Many replication facilities will not even accept jobs smaller than two or five thousand pieces. For high volume disc production, replication is the best way to go.
Now let’s take a look at why DVD-R discs are purple. Like a replicated disc, a recordable DVD-R disc also contains a dye layer sandwiched between two layers of polycarbonate. The difference is that the dye layer does not contain any information when the discs leave the factory – they are blank.
The purple color comes from the Azo chemicals used in the production of the organic dye. This dye crystallizes at a known rate when exposed to a laser, which is what happens when the disc is being “burned.” This gives the burned area of the disc a slightly different color.
Although blank CD-R discs are available in a range of different colors including silver, green, gold, and black, this has not been possible with DVD-R discs so far. With the recent decreases in the price of recordable Blu-ray discs and engineers hard at work on Holographic Versatile Discs, it is not likely that new developments in blank DVD-R media will be explored.
So there you have it! Whether you need to purchase some blank DVD-R discs for yourself or you are looking to get a high volume of DVDs replicated, CDROM2GO is your source for everything DVD! After all, we are Your Duplication Experts!