Night writing visited the National Institute for the Blind in Paris, France, where he met Louis Braille. Braille identified the major failing of the code, which was that the human finger could not encompass the whole symbol without moving and so could not move rapidly from one symbol to another. His modification was to use a six-dot cell, the Braille system that revolutionized written communication for the visually impaired. Night writing Night writing, a.k.a. sonography, was a system of code that used symbols of twelve dots arranged as two columns of six dots embossed on a square of paperboard, and is now
Dot crawl coloration, known as color bleed. Bleed can also make narrowly spaced text difficult to read. Some computers, such as the Apple II, utilized this to generate color. Dot crawl has long been recognized as a problem by professionals since the creation of composite video, but was first widely noticed by the general public with the advent of Laserdiscs. Dot crawl can be greatly reduced by using a good comb filter in the receiver to separate the encoded chrominance signal from the luminance signal. When the NTSC standard was adopted in the 1950s, TV engineers realized that it should theoretically be