The successor to CDs and DVDs, the Blu‑ray disc operates on a similar optical principle but offers a far greater storage capacity, reaching up to 50 GB for dual‑layer versions. Two recording technologies coexist: HTL (High to Low) and LTH (Low to High). HTL discs, thanks to their more stable inorganic recording layer, are generally regarded as the most durable option, making them particularly suitable for long‑term preservation.

In June 2012, the LNE conducted an accelerated aging study comparing several brands of Blu‑ray media. The results highlighted significant differences in quality: Panasonic and Sony discs demonstrated a lower error rate and better resistance to degradation than brands such as JVC and Verbatim. These findings underline the importance of choosing high‑quality media when the goal is long‑term archiving rather than short‑term storage.

Write‑once Blu‑ray discs (BD‑R) offer a distinct advantage over rewritable versions (BD‑RE). Once data is written, it cannot be modified, which eliminates the risk of accidental alteration or corruption. This immutability makes BD‑R particularly appealing for archiving sensitive documents, photographs, or any information that must remain intact over time.

In terms of performance, Blu‑ray offers better transfer speeds than DVDs, reaching up to 72 MB/s depending on the drive and disc quality. However, access times remain slower than those of hard drives or SSDs due to the mechanical nature of optical reading. This makes Blu‑ray more suitable for long‑term storage than for frequent or rapid access.

Beyond capacity and durability, Blu‑ray presents several practical advantages. As an offline medium, it is immune to hacking, ransomware, and remote intrusion, offering a level of privacy and data sovereignty that cloud services cannot match. The physical nature of the disc also protects it from electromagnetic disturbances that can affect magnetic or flash‑based storage. When stored properly, high‑quality HTL discs can remain readable for decades, providing a stable and predictable archival environment.

Nevertheless, Blu‑ray is not without limitations. The need for a dedicated burner and reader—devices that are becoming increasingly rare on modern computers—can be a barrier. Handling large archives may require managing dozens of discs, which can become cumbersome. And while the medium itself is durable, it remains vulnerable to scratches, heat, and poor storage conditions. Finally, long‑term accessibility depends on the continued availability of compatible hardware, a factor that must be considered in any archival strategy.

For backup purposes, Blu‑ray excels in scenarios where data is written once and accessed infrequently. It is particularly well‑suited for “cold storage,” where longevity, stability, and independence from online ecosystems are more important than speed. Users seeking to preserve family photos, legal documents, creative work, or encrypted archives will find Blu‑ray a reliable and cost‑effective solution. However, for dynamic backups that require frequent updates or rapid retrieval, hard drives or SSDs remain more practical.