Test card, also known as a technical card, is a card used in television broadcasting to test the quality and alignment of video cameras. The correct spelling of this word is /tɛst kɑrd/. The first part, "test," is spelled with a short "e" sound (as in "bed") and a "st" consonant cluster. The second part, "card," is spelled with a broad "a" sound (as in "car") and a silent "d" at the end. Although test cards are not commonly used in digital broadcasting, they remain an important tool for engineers and technicians.
A test card is a specialized image or pattern that is displayed on a television or computer screen for the purpose of calibrating, adjusting, or testing the various parameters and performance of the display system. It is typically used during the setup, maintenance, or troubleshooting of television receivers or video game consoles.
Test cards usually consist of a grid-like pattern with various shapes, colors, and alphanumeric characters. These patterns allow technicians or users to assess and fine-tune parameters such as brightness, contrast, color balance, resolution, and linearity. By analyzing the behavior of these patterns, one can determine if the display system is functioning correctly or requires adjustment.
In addition to calibration purposes, test cards are also used to verify the presence and quality of video signals during broadcast or transmission. They ensure that the video content is correctly displayed and transmitted without any interference, loss of information, or technical issues.
Test cards have been widely used since the early days of television broadcasting and continue to be employed in modern digital display technologies. They provide a standardized reference point for technicians, allowing them to accurately assess and optimize the performance of display systems.
The word "test card" is a compound noun formed by combining "test" and "card".
The word "test" comes from the Old French word "test" or "teste", which means "a small vessel or pot used for melting metals or testing their quality". Over time, the meaning of "test" expanded to include general experiments or trials to determine the quality, performance, or suitability of something.
The term "card" has its roots in the Latin word "cardo", meaning "hinge", which later evolved to refer to a flat, stiff piece of paper or cardboard. In the context of broadcasting and television, "card" refers to a chart or image displayed on a screen, serving a specific purpose.
Therefore, "test card" refers to a card, often shown on television screens, used for testing or adjusting various aspects of TV broadcasting, such as colors, contrast, geometry, or signal reception.