When it comes to printing, understanding how different colors appear when mixed together will help you find the right combinations to get the effect that you want. It is important to remember this because colors react differently depending on what format is used.
For example, did you know that if you mixed a red, green and blue light together it will appear white? Yet if you do the same with red, green and blue paints you would wind up with black or a very dark brown?
The reason is because a color that is projected from a source such as light is an “additive” color while colors that are used in printing are “subtractive” colors. The differences are strong enough that you will need to take them into account when printing with particular colors.
Basically speaking, color that has its own source or light is going to react differently when mixed than colors that do not have their own projecting source, but instead reflect the light a certain color. Recently, scientists have been able to create objects that absorb so much light that they are actually difficult to see. This is because what you see when you look at table for example is not really the table, but the colors reflected off the table. If the table absorbed all the light that tried to illuminate it, then we would have a very difficult time seeing it.
The same basic principle is true of printed colors. When you see the color red on a piece of paper for example, the light is striking it with the full range of colors, but the blue and the green is being absorbed while the red is being reflected back.
The Effect of Reflected Light on Color
The subtractive element really comes into play when you start mixing colors for something that is printed or on a surface. If you mix together red, green and blue when painting on a canvas or poster, the result is that you will get a very dark and muddy brown. This is because when the paint is mixed, there is more color being absorbed from the light that is striking it. To keep the colors bright, you will have to mix fewer of them together and the brightest colors are those that are generally the most pure.
A backlit graphic for example also uses subtractive colors and not additive ones even though there is a light source from behind. That is because the colors are absorbing the light source and are not the originators. What is true for printing is also the same for LCD TV monitors that use subtractive colors which are backlit.
So, when you are preparing a printing project and want to add a mixture of colors to achieve a particular effect, remember that you are working with subtractive colors that actually absorb more of the light which means the result may very well be different from the intention. Instead, it is generally better to keep things simple with color when it comes to printing so that they full effect of each can be made. Mixing colors should only be done in pairs, such as purple or orange for example where the color absorption is not so great.