another blog post
By jfrachioni
· 1,640 views
due to my procrastinativity, i now have to due all ten posts in one night. its getting quite bland. i feel like talking about computer screens, as it is what i have been staring at for the last hour. so i shall. most screens are lcd, or liquid crystal display. i dont really know why crystals are involved, but it makes me sound like i know what im talking about. in an lcd screen, there are hundreds and sometimes thousands of small boxes called pixels that make up an image. Typically, each pixel is composed of three sections, each for one of three of the primary colors. as you probably know, the primary colors are all you need to make any color out there, however there are two different sets of primary colors, to be used with different applications. why? one set is the additive primarys and the other is the subtractive primarys. in second grade art class, the primary colors were red, blue, and yellow; the subtractive primarys. these were used because paints and inks and such use subtractive color blending, meaning they absorb, or subtract out some wavelengths of light that hit them, the rest reflecting into your eyes as a specific color. each color subtracts a different wavelength from the original white and reflects only one wavelength, and by blending them you can subtract just the right amount of each from white for your desired color. for computer screens, however, (also projectors, ipods, anything that emits light to create colors), the additive primaries are used, being red, blue, and green, one for each section of pixel in an lcd screen. these are different because with a pixel, colors are created additively, or shining just the right ammount of each wavelength from the different color sections, adding just the right ammount of each for your intended color. for example, you see yellow on a screen because red and green light is hitting your retina, activating some green receptors and some red receptors, which your brain recognises as yellow because it is close to the middle of these two wavelengths. also, white light can only be made with additive primaries, as you add all the wavelengths while black light can only be made by subtractive primaries, when you subtract all the wavelenghts from the original white. doesnt this mean computer screens cant create black? they do so by not adding any color, relying on the background of the screen to absorb light that hits it, so actually, every pixel displaying this text is actually every pixel thats not displaying this text. mind. blown.
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