i kinda understand the difference between subtractive and addictive colours but i don’t understand why we use green instead of yellow for lights
In: Other
When you observe light that shines directly to you (from the sun, from a light bulb), you observe additive colors. The photons go directly into your eyes, and their frequencies “add up” in such a way that the red plus GREEN plus blue frequency equals white.
On the other hand when you are looking at diffused light, for example from a printed paper, the photons from the sun first interact with the paper, and are either absorbed into the paper or reflected to you. If you’re seeing yellow, that means the blue photons have been absorbed, leaving the red and the green to enter your eyes.
The printer inks therefore work with subtractive colors (the ABSENCE of blue, the ABSENCE of green, the ABSENCE of red) in order to print an image in such a way that not printing anything (nothing absent) results in white. The ink colors are cyan, magenta, and yellow, which basically “subtract” red, green, and blue from the photons that will hit your eyes.
It’s basically designed this way so that:
* For direct light, “all” the colors results in white. Computer screens shine / create the light, so powering up all the colors in a pixel will display a white splotch. The typical movie or game screen is rather dark, very rarely is it white with a few words on it.
* For printed paper, “no” color makes you see the white paper, whereas using all colors makes you see black. Powering up all the ink sprayers will create a black splotch.
We usually print a few words or an image on white paper. The majority of the space on the paper is left blank (white). Having to actually “print” / ink a black paper to white would use up a lot of colors. Whereas printing black things on white paper saves color.
Latest Answers