SMPTE color bars
SMPTE color bars are a television test pattern used where the NTSC video standard is utilized, including countries in North America.
[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.
[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.
The graticule of a vectorscope is etched with boxes showing the permissible regions where the traces from these seven bars are supposed to fall if the signal is properly adjusted.
The pluge (short for picture line-up generation equipment) pulse is positioned within the black rectangle, below the red bar (it is present in the illustration but may be hard to see).
When a monitor is properly adjusted, the rightmost pluge bar should be just barely visible, while the left two should appear indistinguishable from each other and completely black.
Typically, a television network, TV station, or other originator of video programming transmits SMPTE color bars together with a continuous 1,000 Hz sine wave before sending program material, in order to assert ownership of the transmission line or medium, and so that receiving stations and intermediary telecommunications providers may adjust their equipment.
[25] Note: Values sourced from "Leader Teleproduction Test Volume 3 Number 4 - Digital Video Levels"[24] The colors below are presented using sRGB transfer of CSS.
Digital test images generated following the RP 219:2002 specifications and adapted to perfectly fit 114 standard and non-standard resolutions for both 16bpp and 8bpp, are freely available in the COLOR dataset of the TESTIMAGES archive.
BT.2111[30] and ARIB STD-B72[31] further added versions with PQ / HLG HDR transfer functions and wide color gamut (BT.2020), which additionally have 100% saturated colors at the top and BT.709 bars at right bottom and left bottom; the 75% gray horizontal bar in the middle is changed to grayscale stair steps.
