Television Is a Unique Medium
[caption id="attachment_114426" align="alignleft" width="150" caption="HDTV"][/caption] Television as a communications medium has had a singular impact on millions of people around the globe, and it wields an impressive influence on how we view our culture. Almost every American home has at least one TV set, and more than 40% of Americans have at least three. Since the 1950s, television has emerged as a global catalyst for social and political change, and has greatly affected how we learn and communicate.
TV lives at home base, It is a facet of our day-to-day lives that we can enjoy alone, or in a group, and its presence in the background can be a source of human contact. With its immediacy, television is, for many people,a primary source of information. TV can feel like a member of the family: familiar, frustrating, and often comforting,TV has created a unique environment of “home entertainment.” What we choose to watch can range from drama of superior quality to programs that challenge good taste. The range of programming comes to us through literally hundreds of channels that are brought to the viewer by cable and satellite, and even traditional rooftop or rabbit ear antennas. Yet television is a consistent source of contention and controversy. Its critics argue that the full potential of tele- vision may never be reached, or that entertainment panders to the lowest common denominator. Ultimately, the validity of these arguments rests on the shoulders of the television producer who has the skills and the capability to put these criticisms to rest.
How TV Works
Television content (a catch-all phrase for programs, news, information, music) comes into a television set through broadcast signals. These signals hold data an image, sounds, graphic art, electronic lettering that is re-created in your TV set as clear images and audio. There are four broadcast signals. Each signal separately controls the:
Brightness of the image
Color of the image
Audio from the image
Synchronization of the transmitter and the receiver (your TV set).Broadcast signals are transmitted through virtually the same radio waves that deliver a radio show. These radio waves travel through the atmosphere at the speed of light, and can accommodate vast amounts of information. Television’s video signals are heavier, don’t travel as far, and use about one thousand times morebandwidth (channel space) than the transmission of an audio signal. With the advances in today’s technology, programming can be transmitted by discrete digital signals delivered viafiber optics, opening up potential levels of interactive use.
The Impact of Human Vision on TV
As we look at an image, this picture stays imprinted on our retina for a fraction of a second. This phenomenon is known aspersistence of vision; as we watch a sequence of rapid images at the right speed (25 to 30 times a second), an illusion is created of a complete and uninterrupted picture.
In early television, scanning wheels created a broadcast picture by scanning an image slowly, line by line; the blurry images on the earliest sets were built with 48 scanned lines. Now, modern color sets reflect a picture that’s comprised of several hundred scanned lines. These lines contain over 100,000 picture elements known aspixels. Our TV screen is coated with fluorescent compounds consisting of millions of miniscule dots that give off light as they’re hit by electrons at high speed.
For an image to be transmitted by electronic impulses, it is first broken down into tiny pixels using a scanning process. Thousands of these pixels form lines that are rapidly transmitted, one line at a time. Even though the screen never has more than one pixel displayed at once, the electron gun scans the screen so quickly that we see a complete picture, not the separate elements it is composed of. Each of these tiny pixels is shaped like a rectangle and is made from three colors: red, green, and blue (RGB). The pixels are combined on a phosphor screen, close enough together that they appear to be just one color. These lines, in order to be seen by the viewer, must be reproduced one by one and rapidly reassembled into the original image. This whole process results in a video signal.
Modern television sets in America receive programming that has been transmitted as 525 rapidly scanned lines; most other countries broadcast in 625 lines, which gives their picture a higher resolution or clearer picture. Early mechanical TVs could only broadcast a 48-line image; the electronickinescope boosted the count to 60 lines. NBC broadcast 120-line images in 1931 and then improved their system to 240 lines two years later. By 1940, NBC had televised a 507-line picture, and one year later, the National Television Standards Committee (NTSC) adopted what has been the American broadcast standard ever since a 525-line, 30-frames-per-second picture called the NTSC format.
A television camera, like a film camera, is pointed at an image, and the opening of the camera’s shutter allows that image to enter the camera. But the way TV captures that picture is different from film. In film, images are captured on film coated with an emulsion that has been chemically treated to be sensitive to light. It is must be developed in a film lab before it can be viewed. In television, the image is transposedelectronically either to videotape or directly to digital storage and can be seen immediately.
Since 1941, standard American TV sets have anaspect ratio of 4:3 and a shape that is almost a square, a little wider than it is tall. More recently,high-definition television (HDTV) has vastly improved our television image.
For example, an HDTV set has a larger aspect ratio of 16:9 and is one-third wider than the current NTSC picture. This aspect ratio accommodates the way our eyes naturally see an image. With HDTV, we see more of what is in our field of vision. It gives the image a finer resolution, with more clarity of detail and almost twice as many lines and pixels as NTSC television. HDTV has smaller pixels that are square rather than rectangular and are closer together.
Regardless of how it may be transmitted or the size of the TV set, television is increasingly a part of our daily culture. TV surrounds us, not only in our homes, but in the office, the supermarket, at dentists’ and doctors’ offices, in a bank line, on a long airplane flight, and even in some New York City taxis. To best study this phenomenon, you need to explore the rich history of television’s early beginnings.
“An unexamined life is not worth living.” If you are interested in developing an art form and you consider yourself to be in an art form, you must, must, must know what came before you. How things work, what the traditions were. The people who are the most informed are people who can take the most risks and be successful. The people who aren’t aware of the history are the very safe ones who don’t change things. They are only building on what’s been done before “
~ Sheril Antoni ~
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