Production Glossary
SECAM
SECAM is the analog color television system that was invented in France, creating Europe’s first color television standard. The acronym stands for “Sequential Color with Memory”. SECAM was invented by a team led by Henri de France. de France began working on SECAM in 1956, but it was a few years before France could convert to the format. A pan-European compromise called for Europe to change to a 625-line television standard. In order to do so, France had to create a brand new network (France 2), which occurred in the early 1960s.Multiple versions of SECAM have been used, ranging from the earliest model SECAM I all the way to the most current version SECAM III B, which was formally adopted as standard in 1967. The first broadcast of color television in France occurred on October 1, 1967 with the image of four men standing in a studio. A countdown from ten ushered in the phrase, “And here is color!”, as the image changed from black and white to full color.
A few European countries (Italy and the United Kingdom) did try SECAM out for a period of time, but eventually switched to the later developed PAL (Phase Alternating Line). All European countries refuse the use of NTSC (National Television System Committee) due to the need for added control in tint.
How It Works
SECAM allows for compatibility with earlier standards of monochrome television. In order to maintain this harmony, SECAM added a signal that carries color information to the original monochrome signal. Luminance (Y) is the black and white signal, while chrominance (C) represents the color signal. By setting the color signal at the end of the monochrome signal spectrum, it reduces the interference between the Y and C signals.
Separation of the two signals is enabled by a sub carrier, which tunes the color signal. SECAM transfers the blue and red color signals separately while utilizing a delay line (an analog memory device) that holds the data from the previous line of color. SECAM also provides chrominance encoding information by the use of frequency modulation on the sub carrier. In order to provide the best quality signal, SECAM’s signals are measured in YDbDr color space.
One of the biggest disadvantages to the SECAM format is that it is not able to be edited conveniently in its’ original form. The frequency modulation SECAM employs causes an invalid SECAM signal to be put out when the signals are mixed. This problem costs time and money to correct and has led to some countries abandoning the format for the more “user friendly” PAL.
Five varieties of SECAM:
- SECAM-L (used only in France)
- SECAM-B/G (used in parts of Middle East, East Germany, Greece
- SECAM- D/K (used in Commonwealth of Independent States and some of Eastern Europe)
- SECAM- H
- SECAM-K (used in French speaking African countries)
- MESECAM is a method of recording SECAM color signals onto VHS video tape. It should not be mistaken as a broadcast standard.
