How do projectors and screens show the color black if black is the absence of light?
In: Technology
This one amazed me when it got mentioned in a VT course.
The black you see is actually white.
Imagine a white wall, on which you project an Excel sheet.
White with black lines. Because you cannot project black light the best you can do is project nothing for the lines and a lot of white light for the white parts.
Now if you don’t project light on a white surface it is still white. But the rest of it is just “more” white or brighter and that makes you think it is black.
That’s why you need a really bright light or a dark room. If the light is not bright enough or if the surrounding light is brighter, you don’t get that level of contrast for your brain to make it black. Then the lines appear to be gray.
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