Subsequently a reflective aluminum layer is sputtered onto the disc covering the bumps follow by a thin acrylic layer which is sprayed over the aluminum for protection. To read something this small you need a very precise reading mechanism. High quality polycarbonate substrates should not exhibit these characteristics. This material will during readout partially block the laser beam in the playback process and could result in a permanent defect in the dye layer. One should carefully examine any CD-R discs under low power magnification and reject any contaminated surfaces.
Many discs fail low radial tracking or contain high jitter characteristics.
Poor quality control at the mastering or molding is normally the cause. Such discs will read on some drives but fail in others. This is normally caused by either mastering or molding flaws. Other discs contained uncorrectable errors. Severe defects are often caused by recording systems such as absent or short post gaps, high jitter, and severe error correction algorithms which result from flaws in the recordings software or in the CD-R drives themselves.