Color Theory

Now with the invention of color displays red , green and blue were chosen as the primary colors as they matched the three color sensitive tones in the retina of the human eye. You see paper reflects light and each ink you put on it will reduce the light that would have otherwise been reflected. In other words it subtracts one color from white and that’s why CMYK is known as a subtractive color system as it is used for printing on paper . However unlike paper that reflects light the colors that we see on a digital device are created by combining colors with a transmission of light from the backlit screen. In Photoshop if we start with darkness or black when you add a

red brush stroke and then blue on top of it and change the blend mode to “screen” . Why screen blend mode? The name says it all . It adds colors to create new colors the

way display screens do and if I create another layer and add green on it as soon as I said the blend mode to screen we get white with a red,green and blue colors mix that’s why RGB is known as the additive color system.

Take a look at this image for example you can see I have separated it into three layers: first one is red , second layer is green and then blue. So every single image in photoshop or any screen you actually use is made up of only three colors red , green and blue and if you take a look at the black and white gradient you will see that even what we’ve perceived as luminosity is actually made up of red, green and blue colors and this is completely opposite to the subtractive color mixing of CMYK to do any color correction in Photoshop you will have to memorize the RGB color wheel where red is opposite of cyan, green of magenta and yellow of blue. This is also known as the CMYK color wheel because CMYK predicts RGB by many years. But it’s one and the same thing so which color wheel should be used to create color harmonies? In my opinion there is no color wheel that can fully describe the complexities of how we perceive color from light. Remember that color wheels are merely a guideline and it’s ultimately up to you to define the implications of your color palette.