What’s the Difference Between DVD Replication and Blu-ray Replication?

By · Friday, February 11th, 2011

Difference Between DVD Replication & Blu-ray Replication?At first glance, a DVD disc and a Blu-ray disc look almost identical. They are the same size, shape, and very close in weight. They both store movies which can be played back on a computer, game console, or home theater system. Both DVD and Blu-ray discs can also be used for storing computer data files. With all the similarities, you might be surprised to learn that the discs are in fact very different from each other.

While DVDs and Blu-rays look and work the same, the manufacturing process for each type of disc is entirely different. Let’s take a closer look at how the discs are produced and learn about the differences between DVD replication and Blu-ray replication.

DVD movies sold in retail stores are replicated discs, which are also known as a “stamped” or “pressed” discs. These discs are made in specialized factories called replication plants, which can produce hundreds to tens of thousands of discs per day.

The process of making a DVD disc begins with a glass master disc. The glass master contains all of the information that will be on the finished disc. The disc is electroformed and used to make additional masters. While this is happening, a machine is carefully measuring out tiny pellets of polycarbonate plastic which will become the disc.

These pellets are subjected to intense heat and pressure as they enter the injection molding machine, where they take on their signature 120mm circle shape. The glass master is stamped into the liquid plastic which is then cooled, metallized, cleaned, bonded, and UV cured.

At this point, the artwork is applied to the discs with a large-volume screen printing machine. Once they are printed, the discs are inserted into their cases or packaging and boxed up for delivery.

The process behind Blu-ray replication is similar in theory to DVD replication, but with several extra steps thrown in. Replicated Blu-ray discs are requires to have AACS copy protection, which we discussed in a previous article about replication. This technology prevents the disc contents from being copied illegally. A proper AACS license can easily add several hundred to a few thousand dollars to the cost of replication.

Another difference between DVD and Blu-ray replication is that Blu-ray discs are hard coated while most DVD discs are not. Hard coating provides an extra durable barrier that protects the disc’s data layer from scuffs, scratches, and other damage. This greatly reduces the chances of read errors and other playback issues for the user.

Finally, many Blu-ray discs feature two data layers for a total of 50GB of storage. The second layer is applied to the disc using a wet embossing process. Applying this layer is an extremely precise process which must be accurate to within 25 plus or minus 1 microns.

When you consider the technology that goes into making a disc, it’s really quite amazing! I hope this article has been useful in highlighting some of the technical differences between DVD replication and Blu-ray replication.

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