Test card designed in 1956 to be used with black and white analogue TV systems
EIA 1956 video resolution targetOff-air photo of EIA 1956 test card being broadcast by offshore pirate station TV Noordzee, 12 August 1964Off-air photo of RMA 1946 Resolution Chart being broadcast by Dutch public broadcaster NTS, 7 September 1961
The EIA 1956 Resolution Chart[1][2] (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,[3][4] based on the previous (and very similar) RMA 1946 Resolution Chart.[5][6] It consisted of a printed chart filmed by a TV camera or monoscope to be displayed on a TV screen, and was also available as individual rolls of test film to test broadcasting equipment.[7][8] Inspecting the chart allowed to check for defects like ringing, geometric distortions, raster scan linearity, cathode-ray tube uniformity and lack of image resolution.[9][10] If needed, a technician could use 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.[3][11][12][13][14][15][16]
The chart is composed of several features, each designed for a specific test:[17]
Large white circle: Allows for image geometry adjustments (image should be centered with the circles being perfectly round).
Vertical stripe boxes: A grating with a resolution of 200 Television Lines (TVL), a measurement of image resolution on analogue TV systems, allowing adjustment of horizontal linearity and geometry.
Horizontal stripe boxes: A grating, allowing adjustment of vertical linearity.
Grayscale steps: Evaluating gamma and transfer characteristics, they allow for contrast and brightness adjustments (at least 6 to 8 steps should be visible)
Concentric circles: Allow to test cathode-ray beam sharpness and focus
Resolution wedges: The gradually expanding lines near the center, labeled with periodic indications of the corresponding spatial frequency, allow checking of image resolution.
Numbers: Going from 200 to 800, they correspond to TV Lines (TVL).
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).
This chart, in conjunction with the RMA 1946 Resolution Chart[35] and later widescreen patterns, is commonly used to test consumer and professional standalone, smartphone and tablet cameras for photo and videography[12] and other imaging equipment like microscopes[9] or CCTV cameras.[11][36]
Some variations of the EIA resolution test chart exist. Two Japanese variants of the EIA 1956 resolution chart are called "ITE Resolution Chart /EIAJ Test Chart A"[37] and "JEITA Test Chart II".[38] A widescreen update of the EIA 1956 resolution chart was developed around the 1980s for the HD-MAC broadcasting standard,[39] which was later modified by the Institute of Image Information and Television Engineers of Japan as its ITE Resolution Chart for High-definition Televisions.[40][41]
The centre portion of the RMA 1946 Resolution Chart was featured on the cover of Die Kreuzen's 7" single of Pink Flag/Land of Treason, released in 1990.[52]
^Lamminen, H; Ruohonen, K; Uusitalo, H (May 2001). "Visual tests for measuring the picture quality of teleconsultations for medical purposes". Computer Methods and Programs in Biomedicine. 65 (2): 95–110. doi:10.1016/S0169-2607(00)00120-6. PMID11275330.