testbilder

Testbilder, or test patterns, are static images or sequences used to calibrate and test video equipment, transmission links, and display devices. They provide reference content for evaluating geometry, color accuracy, gamma, contrast, brightness, resolution, and signal integrity. Historically used when a television channel was off air or undergoing maintenance, testbilder remain in use in studio workflows and in some consumer display calibration tools.

A typical testbild combines several elements to support different calibrations. Color bars or a color chart enable chromatic calibration, while a grayscale ramp assists with white balance and contrast assessment. Geometric patterns such as grids, lines, and crosshairs help test scan geometry and aspect ratio, and circles or dot patterns aid resolution and alignment of various display technologies. Some versions include a clock or timing indicators to verify frame rate and synchronization.

Origins and usage: Test patterns date from the early days of analog television. In the United Kingdom, test cards such as Test Card F became iconic, while in Germany and other European countries testbilder were widely used by broadcasters to allow technicians to calibrate equipment. With the move to digital broadcasting and file-based production, traditional testcards remain in use in production and for device calibration, though new digital patterns and software-based testers have become common.

In modern practice, testbilder are used in broadcast engineering, post-production, and display calibration. They are available as on-screen patterns in professional video routers, encoders, and in consumer display menus, and can be downloaded from broadcasters and testing organizations. They help ensure consistent color, brightness, and resolution across devices and media formats.

See also:

- Color bars

- Grayscale patterns

- Test card F

- Video calibration