Why purchase and archive 35mm film prints, which can cost around $15,000, when a Blu-ray disc is available for $35? Why do Hollywood studios create 35mm backup prints for films that are now filmed, edited, and screened digitally? The very brief reply would focus on three points:
1. Image and sound quality: A 35mm print in good condition is vastly superior to any available home-video format and even many of the most high-end professional formats.
2. Length of preservation: Carefully archived 35mm prints will last well over 100 years, and by some estimates over 400 years (Jan-Christoph Horak, Director of the UCLA Film and Television Archive); in comparison, digital preservation is dogged by regular technological obsolescence and the connected costs. It is also unclear how long some storage formats will even last, much less for how long older formats can be decoded.
3. Cost of preservation: 35mm film preservation is well established and fundamentally simple - keep cool, dry, and safe. Professional digital preservation is complicated and costly and requires frequent switches between technologies, formats, and platforms - much more expensive and less stable in the long run.