SMPTE color bars

"Color bars" redirects here. For segregation by skin color, see Racial segregation. For other uses, see Color Bars (disambiguation).
Rendition of SD ECR-1-1978 color bars Colors are only approximate due to different transfers and color spaces used on web pages (sRGB) and video (BT.601 or BT.709)

SMPTE color bars are a television test pattern used where the NTSC video standard is utilized, including countries in North America. The Society of Motion Picture and Television Engineers (SMPTE) refers to the pattern as Engineering Guideline (EG) 1-1990.[1] Its components are a known standard, and created by test pattern generators.[2][3][4] Comparing it as received to the known standard gives video engineers an indication of how an NTSC video signal has been altered by recording or transmission and what adjustments must be made to bring it back to specification. It is also used for setting a television monitor or receiver to reproduce NTSC chrominance and luminance information correctly.

A precursor to the SMPTE test pattern was conceived by Norbert D. Larky (1927–2018)[5][6] and David D. Holmes (1926–2006)[7][8] of RCA Laboratories and first published in RCA Licensee Bulletin LB-819 on February 7, 1951. U.S. patent 2,742,525 Color Test Pattern Generator (now expired) was awarded on April 17, 1956, to Larky and Holmes.[9] Later, the EIA published a standard, RS-189A, which in 1976 became EIA-189A, which described a Standard Color Bar Signal, intended for use as a test signal for adjustment of color monitors, adjustment of encoders, and rapid checks of color television transmission systems.[10] In 1977, A. A. Goldberg, of the CBS Technology Center, described an improved color bar test signal developed at the center by Hank Mahler (1936–2021)[11][12] that was then submitted to the SMPTE TV Video Technology Committee for consideration as a SMPTE recommended practice.[13] This improved test signal was published as the standard SMPTE ECR 1-1978. Its development by CBS was awarded a Technology & Engineering Emmy Award in 2002.[14] CBS did not file a patent application on the test signal, thereby putting it into the public domain for general use by the industry.

Early concept of color bar test pattern
Recreation of EIA-189A color bars without castellations

An extended version of the SMPTE color bars, SMPTE RP 219:2002[15] was introduced to test HDTV signals (see subsection).[16]

Although color bars were originally designed to calibrate analog NTSC equipment, they remain widely used in transmission and within modern digital television facilities. In the current context color bars are used to maintain accurate chroma and luminance levels in CRT, LCD, LED, plasma, and other video displays, as well as duplication, satellite, fiber-optic and microwave transmission, and television and webcast equipment.

In a survey of the top standards of the organizations' first 100 years, SMPTE EG-1 was voted as the 5th-most important SMPTE standard.[17]

  1. ^ EG 1:1990 - SMPTE Engineering Guideline - Alignment Color Bar Test Signal for Television Picture Monitors. March 1990. pp. 1–3. doi:10.5594/SMPTE.EG1.1990. ISBN 978-1-61482-000-0. Archived from the original on April 14, 2017.
  2. ^ NTSC and NTSC/PAL/SECAM Test/Sync Generators (PDF). Leader.
  3. ^ Model 408NPS INSTRUCTION MANUAL (PDF). Leader. p. 5.2.
  4. ^ CG-931/2 - Color Pattern Generator (PDF). Kenwood. p. 16. Archived from the original (PDF) on 2022-07-27. Retrieved 2022-07-27.
  5. ^ "Norbert David Larky Obituary (1927 - 2018) Los Angeles Times". Legacy.com.
  6. ^ "The History of TV Color Bars, One of the First Electronic Graphics Ever Made". www.vice.com. 20 July 2020.
  7. ^ "David D. Holmes Obituary (2006) The Times, Trenton". Legacy.com.
  8. ^ "Email from The Inventor of Color Bars". March 30, 2009.
  9. ^ US patent 2742525, Norbert D. Larky, Somerville & David I. Holmes, New Brunswick, N.J., "Color Test Pattern Generator", issued April 27, 1956, assigned to Radio Corporation of America 
  10. ^ "CTA - EIA-189 Encoded Color Bar Signal". Standards.globalspec.com.
  11. ^ Hank Mahler, developer of the SMPTE color bars, passes away, from TVTechnology.com, October 13, 2021
  12. ^ "Danbury CT Funeral Home and Cremation Center | Danbury Memorial Funeral Home and Cremation Service LLC".
  13. ^ Goldberg, A. A. (June 30, 1977). "A Monitor Alignment Color Bar Test Signal" (PDF). Proceedings, 31st Annual Broadcast Engineering Conference, National Association of Broadcasters. 31: 84–85.
  14. ^ "Outstanding Achievement in Technical/Engineering Development Awards" (PDF). National Academy of Television Arts and Sciences. 2009-03-26. Archived from the original (PDF) on March 26, 2009. Retrieved 2018-05-25.
  15. ^ High-Definition, Standard-Definition Compatible Color Bar Signal. June 2002. pp. 1–15. doi:10.5594/SMPTE.RP219.2002. ISBN 978-1-61482-230-1. Archived from the original on June 15, 2018.
  16. ^ "TESTIMAGES". Testimages.org.
  17. ^ Howard Lukk. "Countdown to History – 100 Years of SMPTE Standards Development". Us9.campaign-archive.com.