The Apple II computer are unique in that not only was it the first home computer ever released to the mass market, it was the first computer released

Nerdly Pleasures: Apple II Composite Artifact Color - NTSC, PAL and Filters

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2021-12-06 22:00:10

The Apple II computer are unique in that not only was it the first home computer ever released to the mass market, it was the first computer released to support color graphics, all the way back in 1977.  It worked by exploiting quirks in the NTSC color system called artifact color which TVs were attempting to suppress.  The design of the Apple II was so solid that its color works rather well on almost anything that can accept a composite signal, even today.  But the color method used did not translate to PAL countries and later improvements to color filtering could modify the colors shown.  In this article, let's take a deep dive into how artifact color works on the Apple II and how it was adapted for systems where artifact color could not exist and how artifacts can change according to the display technology inside a display.  

Artifact color is based on a quirk of the NTSC method of decoding color.  A color NTSC signal is made up of three components, brightness/luma, color/chroma and sync.  Brightness and sync were present when the NTSC defined as the black and white television standards in 1941.  Color was added to by the NTSC to be backwards compatible with the black and white standard in 1953.

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