When most of us think about combining colors, we think about mixing different colored paints.
So we know that when we mix yellow and red we get orange, or yellow and blue, we get green. We get used to this type of color mixing as children and we may think of this as adding one color to another.
In fact, this type of color system (mixing paints) is termed the subtractive model. You will see why this is used in the second tutorial.
First let us look at how color is mixed on the computer screen.
The computer screen uses the primary colors Red, Green and Blue.
When you add red light to green light you get yellow light. That is quite different from when you mix paints up! You can test this out for yourself with three flashlights and some plastic or glass colored filters.
Complete light is white light, and its main three elements are red, green and blue. By added two elements together you get the new color.
When you add red filtered light to green light and shine it on a white wall, you get yellow. By changing the amount or strength of the red compared to the green will change the shade of yellow. adding more red will cause an orange to be produced.
Adding blue light will complete the missing elements and the result will be white. You can see this in the color chart opposite.
Because you are adding proportions of the three main colors Red, Green and Blue - RGB, this is called the additive model or the RGB model.
Computer screens use the RGB model to create colors on the screen.
A computer program can use a value of 0 to 255 for each of the main colors and this huge variation allows millions of colors to be created.
Black is not a color, it is the absence of any light. So the black print on this page is in fact not projected on to the screen, it is areas that are left where nothing is projected onto the screen! It is the opposite of writing on a piece of paper.
The basic advantage of RGB model is it's has wide range of colors making it useful for full color editing. But at the same time this model is said to device dependent. This means the way colors displayed on the screen depends on the hardware used to display it.
In the second tutorial we will look at the other model: CMYK and see the relationship between computer screen color and printing color.
