Plugelements

Plugelements, also called PLUGE elements, are components of video test patterns used to calibrate the black level and the lower end of a display’s luminance range. They are most commonly seen as part of the PLUGE section in traditional analog color-bar patterns.

Construction and placement: A PLUGE pattern typically includes a reference black field followed by one or more sub-black fields that are offset from black by a small amount. The fields are placed at the bottom of the test pattern and are often paired with color bars. The exact offset and the number of sub-black fields vary by standard (such as NTSC or PAL).

Purpose and use: Technicians use plugelements to judge whether the display renders shadow detail correctly and to set the proper black level and gamma. By observing whether the sub-black areas disappear, remain visible, or blend into pure black, the operator can adjust the video signal or display controls to the desired level. In waveform monitors or scopes, the pluge fields provide a visual reference for black clipping and dynamic range.

Standards and context: Plugelements are part of broadcast test patterns and have historical prominence in maintaining consistent black level across equipment. With digital video, modern calibration tools replicate the pluge concept in software-based test patterns; exact luminance values may differ by standard but the principle remains the same. They are primarily used in professional contexts, though related patterns may appear in some consumer test material.

See also: Color bars, grayscale, black level, waveform monitor, SMPTE patterns.