EIA 1956 resolution chart
The EIA 1956 Resolution Chart (until 1975 called RETMA Resolution Chart 1956) is a test card originally designed in 1956 to be used with black and white analogue TV systems, based on the previous (and very similar) RMA 1946 Resolution Chart. It consisted of a printed chart filmed by a TV camera and displayed on a TV screen. Inspecting the chart allowed to check for defects like ringing, geometric distortions, raster scan linearity, cathode-ray tube uniformity and lack of image resolution. If needed, a technician could used it to perform the necessary hardware adjustments. Today , this chart continues to be used to measure image resolution of modern cameras and lenses and also in scientific research. Features and operation. The chart is composed of several features, each designed for a specific test: Used with early monochrome TV systems, this chart was useful in measuring image resolution, determined by inspection of the image as displayed on a CRT. On such systems an important measure is the limiting horizontal resolution, affected by hardware and transmission quality (vertical resolution is fixed and determined by the video standard used, usually 525 lines or 625 lines). Usage. This test card was  transmitted by NRK in Norway (in conjunction with the monochrome Pye Test Card G), CKCK-TV in Saskatchewan, Canada (525-lines variant), RTBF and VRT in Belgium, NTS in the Netherlands, Magyar Televízió in Hungary, TVP in Poland, American Forces Network in West Germany (525-lines variant, sometimes also with the centre portion overlaid on top of Multiburst test pattern), Yugoslav Radio Television in the former SFR Yugoslavia, Rediffusion Television in British Hong Kong (where it replaced a modified version of the 1950s Marconi-designed Associated-Rediffusion "diamond" test card), Egypt and Syria. It was also used by the pirate  TV Noordzee station broadcasting to the Netherlands in the 1960s. This chart, in conjunction with later widescreen patterns, is commonly used to test consumer and professional standalone, smartphone and tablet cameras for photo and videography and other imaging equipment like microscopes or CCTV cameras. Variations. Some variations of the EIA resolution test chart exist. In continental Europe, a variation know as Telefunken Test Card T05 was used. It had five diagonal bars on the top left of the center white circle and different resolution wedges reminiscent from the RMA 1946 Resolution Chart. It was used on ARD (from the 1950s  up to the 1970s), Hessischer Rundfunk, Bayerischer Rundfunk, WDR, NWRV in northern Germany, Yugoslav Radio Television, Österreichischer Rundfunk in Austria, BRT in Belgium, Doordarshan in India, Corporación Estatal de Radio y Televisión in Dominican Republic (525-lines variant; in conjunction with Indian-head test pattern), some commercial TV stations in Australia, Israel Broadcasting Authority and Israeli Educational Television in Israel, and in early-1950s trial television tests by the KTH Royal Institute of Technology in Stockholm, Sweden. A modified Telefunken T05 test card was also used by Anglia Television, the ITV franchise holder for the East of England in the 1960s , designated as its own "Test Card B" (not to be confused with the BBC's never-aired Test Card B from the 1940s).