DVD CDs (0.74 µm for DVD versus 1.6 µm for CD), accounting in part for DVD's increased storage capacity. In comparison, Blu-ray Disc, the successor to the DVD format, uses a wavelength of 405 nm (violet), and one dual-layer disc has a 50 GB storage capacity. Read and write speeds for the first DVD drives and players were 1,385 kB/s (1,353 KiB/s); this speed is usually called "1×". More recent models, at 18× or 20×, have 18 or 20 times that speed. Note that for CD drives, 1× means 153.6 kB/s (150 KiB/s), about one-ninth as swift. DVD-Video is a standard
Picture disc unhappy with their quality and soon began making an improved type. A rigid blank shellac core disc was sandwiched between two illustrated sheets and each side was then topped with a substantial layer of high-quality clear plastic into which the recording was pressed. Like nearly all records being made for the general public, they were recorded at 78 rpm, but one issue was recorded at 33⅓ rpm, a speed already in use for special purposes which Victor was then unsuccessfully attempting to introduce into home use. It was the first 33⅓ rpm picture disc and the only one made until