CD/DVD vs. Blu-ray

Even though a Blu-ray (BD) looks the same as a CD or DVD, that’s where the similarity ends. Unlike a CD/DVD, a BD has a Hard Coating.  This Hard Coating, located on the playing side of the disc, protects it from scratching.

With CDs/DVDs, you can safely remove between 200 to 300 microns of polycarbonate for deeper scratches.  On BDs, the Hard Coating is only 5 microns thick.  This means you only have 3 microns of repairable depth before making the Blu-ray unplayable.