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I have noticed that a lot of people are confused about color and how it works. This little article will explain how color works and how it's different for print and onscreen. (Only newsletter subscribers will get this article ...that's you)

Ok you better fasten your seatbelts because we are going to take a crash course through color theory at warp speed. Understanding color is a vital piece of knowledge for your graphics career.

There are 2 types of color, one called additive and one subtractive. With additive color all the colors added together make white. As the sunlight reflects off objects they absorb different colors. What is left over is the color that our eyes perceive. This type of color is what occurs in the real world. We know that the 3 primary colors, red, yellow and blue enable us to create any color we wish. For example (in terms of primary colors) when sunlight hits an orange, the orange absorbs the color blue. As a result, yellow and red are left over and, combined, make up an orange color visible to the eye. In other words; take white and remove blue and you have orange

Of course in the real world we are dealing with more colors than just the 3 primary colors. Take a rainbow and you will see all the colors in the spectrum. A Prism is another example, shine a pure white light at just the right angle and you will see the color split into red, orange, yellow, green, blue, violet and indigo. The same process occurs, using raindrops as prisms, when a rainbow appears.

Another example is the ocean. Have you ever wondered why everything deep in the ocean appears to be blue? That is because the colors red, orange, yellow and green are less dense than blue and are filtered out by the time they reach a certain depth. That is why underwater photographers carry a large flashlight, to restore the colors in the depths of the ocean.

A good way to demonstrate this would be to take a round piece of cardboard and paint red, yellow and blue on it and spin it really fast, you would notice that as it spins, the colors mixed together become white.

A monitor works a little differently, in that the primary colors used are Red, Green and Blue. That is where the name RGB comes from. Theses colors are called RGB Primaries. There are 3 guns inside the monitor shining these 3 colors onto the screen that we see. These 3 colors mixed together form the various colors possible on a color monitor. A monitor is an example of additive color.

The 2nd type is called the subtractive color. Where we subtract color to make up white. We are most familiar with this color model when we mix paints etc. This is also how a printer works.

However a commercial printing press works a little differently. It uses a CMY color space. This means that the primary colors used are Cyan (bright blue), Magenta (purple- red) and yellow. Because these 3 colors mixed together make up a weak black, the color black is also added. That is where we get the name CMYK, black is represented as “K” – key – so we don’t get it mixed up with blue. This is the information we need to know when we are designing for a commercial print job.

When we print on a 4 color commercial printing press, its actually called 4-color process printing. In a nutshell, the 4 colors are arranged into different dots at varying sizes and angles to fool the eyes into seeing the different colors. If you look at a printed piece with a magnifying glass you will notice that the image is made up of tiny dots.

Each color mode is called a color space. The range of possible colors with each color space is called a color gamut. Gamut are there because a human eye is capable of seeing more colors that presently reproducible on a monitor or print. The gamuts are the colors that are reproducible. A CMYK color space is smaller than that of an RGB meaning that there are fewer colors available. The reason that the CMYK gamut is smaller than that of the RGB is because you cannot reproduce with ink all the colors you can produce on a monitor. You will notice that you will lose some brightness and vibrancy when converting to CMYK. In the color picket you will notice an out of gamut warning: a little triangle.

Working in CMYK without working in CMYK

When working in CMYK you will notice that not all the filters are available and the computer runs slower. (Because of an extra channel your file size is 1/4 larger)

But your colors are not true for printing in RBG mode. The solution? fool your computer into thinking you are in CMYK mode.

Choose View>proof setup>working CMYK. Now work in RGB mode and press Cmd/ctrl+Y to toggle between RGB and CMYK preview. The title bar in the image window will indicate which mode you are in.

Don’t forget to save a copy in CMYK for printing when you are done.

Changing multiple Text layers at once