Check the Above Black bar. It should still be faintly visible. If it has disappeared, your brightness is too low. 4. Fine-Tuning

The PLUGE pattern remains an indispensable tool in the repertoire of video engineers and calibrators. Its elegant simplicity—a visual representation of the threshold of visibility—allows for the objective alignment of subjective visual perception. While modern display technologies like Local Dimming LCDs and OLEDs introduce new variables regarding dynamic processing and absolute black levels, the fundamental logic of the PLUGE signal persists.

While the concept remains the same, the "numbers" change depending on your content:

The standard SMPTE color bars include a in the bottom right corner. It consists of three small vertical bars:

The calibration process using PLUGE relies on the principle of :

HDR calibration is more complex because OLEDs and LEDs handle "near-black" differently. However, many HDR test suites still use a version of the Pluge pattern to ensure the display's tone mapping isn't "clipping" shadow detail. The Bottom Line

The PLUGE signal was originally conceived by the British Broadcasting Corporation (BBC) in the 1960s. It was initially developed as part of the "Picture Line-Up Generation Equipment" hardware, used to align studio cameras and monitors. The intent was to provide a simple, objective method for engineers to set the luminance gain and offset of monitors in a standardized manner.