BD-R is the recordable blu ray disc format. This type of media is considered a write-once format because once the disc is full of content it cannot be erased and reused. It is comparable to the CD-R and DVD-R or DVD+R formats except that the blu ray recordable disc has higher capacity and requires a blue laser in order to read and record the disc. The Blu Ray recordable discs initially could only have one information layer for storage or two information layers for storage (also known as dual layer discs).
However, in 2010 a couple of other variations were introduced. The new three and four layer data storage discs are known as the XL versions. The three layer BD recordable is the TL and the four layer recordable disc is the QL. The single and dual layer BD-R discs are also available in two sizes. The CD size is 12 cm or 4.75 inches and there is also a smaller size disc that is 8 cm or about 3.25 inches in diameter. The approximate capacities of these various recordable blue ray discs are given below:
The recording layer in these blu-ray recordable discs is either a dye layer as is used in the CD and DVD recordable formats or an inorganic material. The longevity of these discs is uncertain and there has been no independent testing to try and approximate the lifetime. Manufacturers of the media are stating lifetimes of 30 to 200 years, but further research is required to provide some validation to these numbers.
Blu ray recordable discs should be handled and stored like CDs and DVDs. Avoid touching the disc surfaces, store in a regular size jewel case that is placed vertically on a shelf, do not write on the disc, do not place adhesive labels on the disc, and avoid warm and humid storage conditions.
This recordable format does provide substantially more storage space than CD-Rs and DVD-Rs can provide. Therefore, it has the potential to be a very useful format, especially for the storage of large files such as very high quality digital photographs and digital video. However, because the format has not been adopted widely in the marketplace and because the longevity of the media is uncertain, it is best to wait a while until using this type of disc as a long-term storage format.