What is the name of the segment at the beginning of a master tape that includes color bars and test tones?

The segment at the beginning of a master tape that includes color bars and test tones is referred to as the preamble. This section serves an essential purpose in video and audio production, as it allows technicians and editors to calibrate their equipment for optimal performance before the actual content begins. The color bars provide a reference for color calibration, ensuring the visual quality remains consistent, while the test tones are used for audio calibration, allowing sound levels to be adjusted correctly. The preamble thus plays a critical role in maintaining quality control and ensuring that both video and audio signals are set to the desired standards before the main production content is played.