How to create letters and numbers by computer.
Character Generators
Character generators (CGs) were the first digital graphics units. A CG looks something like a computer terminal. It is, in fact, intended to be used like a word processor. Many of the editing features now used on electronic word processing systems were first used on CGs. CGs allow you to type titles onto the TV screen. If you want to make credits for who wrote, produced, directed, and starred in the show, use the CG. If you're interviewing someone and you want to flash a name up on the screen so the viewers know who the person is, use the CG.
The earliest CGs were very simple. They only produced white lettering on black background for use as “keys.” There were one or two type sizes, and only one or two type styles (fonts). But now you can do white on black lettering, or you can give the letters any color you want and produce a colored background. You can make the letters an outline, or solid, or solid with an outline. There's a wide variety of sizes and fonts available; the range is amazing. To be most effective, character generators also need to have an extensive memory. CG memories used to be measured in pages. One complete video frame of information was a page. When titles were just simple lettering it was easy to define the number of pages in the memory. With the addition of colors, shadows, outlines, and movement, the memory needed to make up a page varies with the complexity of the image. Pages are no longer a valid way to measure character generator memory. Today, we measure CG memory just as we would for any other computer. If you're preparing a show that has opening titles, names inserted during the show, and closing credits, you're going to need a lot of information. If the show is shot live, this is too much to be typed as it's needed. However, you can enter all the information into the CG's memory before the show begins. Then it can be brought out of the memory when needed. Of course, what is really happening is that the CG is generating a series of numbers. But the main control unit will still look very much like a standard computer terminal.
Components of a typical character generator.