Remember those exam questions that asked you to “compare and contrast” two things, like the American Revolution and the French Revolution? (Quick answer: the French Revolution had the guillotine, the American didn’t.) I always wondered why they had to specify both. I mean, a comparison would yield both the similarities and the differences, wouldn’t it? I think they were just trying to make it clear that they wanted you to address the similarities and differences, so you didn’t give an answer like I did. I checked the definition of both, and “compare” emphasizes the similarities, while “contrast” emphasizes the differences. So now you know.
In the olden days, i.e. when I was growing up, TV sets had a whole bunch of knobs that you could turn and play with, ostensibly to make the picture as good as possible to enhance the enjoyment of the programming being broadcast. There were the horizontal and vertical hold, which would stop the picture from rolling, an adjustment for the height and width of the picture, and a couple called “brightness” and “contrast.” In the black-and-white days (which for some of us lasted until the mid-Seventies) you did this using the ever-popular “Indian Head” test pattern.
Whenever I was bored and the only one at home, I would play with these and see what they did. I never quite got the difference between brightness and contrast, though, except you could make the picture really bright or totally black it out with the brightness control. It was kind of like a piano, which has three pedals, but most people only used the right-hand one, the “sustaining” pedal. For the other two, you had to look them up in the encyclopedia, and even then, lotsa luck figuring it out.
As TV broadcasting became more geared to color, the Indian Head was replaced by the color bars.
If you watched them on a B&W (black and white) TV set, they looked like this.
Ray Rayner used to have a morning cartoon show in Chicago, and for a while he would show the color bars on his show so people could adjust their sets, and tell you what color each one was (white, yellow, cyan, green, magenta, red, blue). All I was seeing was shades of gray.
I learned later that was called “grayscale,” a word I wish I knew when CBS Television started broadcasting in color. (Don’t want to get into why CBS was the last network to broadcast entirely in black and white right now.) The first night they were broadcasting in color, I noticed that the cartoon opening for My Three Sons went from black and white to shades of gray. My brothers thought I was crazy when I said I could see where the colors went, thinking I meant I could actually see the colors on our B&W set. Of course I couldn’t see the colors, but I could see that the picture looked different, because instead of just black and white, I was seeing grayscale.
NBC, which was owned by electronics manufacturer RCA, was the first “all color” network in the United States. They opened their programs with this.
Of course, there was the night in 1968 when they broadcast A Hard Day’s Night, my favorite movie of all time, which starred The Beatles and was shot entirely in black and white. This was what they played before that broadcast.
I distinctly remember the night it was on. My mother came home that afternoon and informed us that we would be attending some sort of special assembly at her school that evening, because she had to be there and she couldn’t find a sitter. I was not happy I’d be missing the movie and made it clear I was going under protest. She wasn’t really pleased.
Anyway, according to this page, brightness is an absolute value determined by the R, G, and B values of a given image, while contrast is a relative term that expresses how bright an object in a picture is relative to its background.
There will be a quiz next week…
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