There is a difference between print colors (CMYK) and screen colors (RGB). There are a few things you need to know about print colors and ink coverage when designing artwork for printed media.

This video explains all you need to know to be sure you will create perfectly printable artwork files.

Most images you see on your phone, tablet and computer are made up of pixels, each pixel colored by three values: red, green and blue. In fact, when you look closely at your screen, you may just be able to see that each pixel is actually made up of three subpixels. One red, one green and one blue. The combination of the brigtness of each subpixel determines the overall color of that pixel.

Printed media is not created using red, green and blue pixels, in stead, each pixel is made up of ink dots in the colors cyan (blue-ish), magenta (red-ish), yellow and black (CMYK). So when you want to print an image that is constructed using red, green and blue (RGB) pixels, you need to convert it to an image with CMYK colors. This can be done using image editing software, like Photoshop.

Ink coverage
Each CMYK pixel is created using a percentage of each ink color. The more percentages are used to create the color of a pixel, the darker the pixel will get and the higher the ink coverage for that pixel will become. The ink coverage is the total percentage of ink of a pixel.

There is one thing you need to know about ink coverage: you can have too much of it. If you want to create a dark color, like a very dark red, you might choose to create this color using 80% cyan, 100% magento, 80% yellow and 100% black. This would add up to a total ink coverage of 360%. This value is too high meaning too much ink is used for this pixel. It may cause it to spread, blend with neighbouring pixels and eventually smear. You don't want this. To avoid this, you should use a maximum ink coverage of 330%. (This is an absolute maximum. To be on the safe side, using 300% as a maximum target ink coverage is smart.)

Fortunately, if you create a document in Photoshop, Illustrator or InDesign, you can set the color profile of the document to Coated FOGRA 39, which will keep an eye out for you, to avoid ink coverage to be higher than 330%. You can set the color profile of your document in the menu, below color, next to Color Profile. When you select a color in the color picker, even a dark or black color, the ink coverage will never be more than 330%. Handy! (Note that you can still edit individual CMYK values of a color, making the ink coverage too high, so please keep that in mind.)

CMYK black
Now that you know all that you need to know about ink coverage, you will realize that you can't create black, simply by setting the CMYK values to 100%C, 100%M, 100%Y, 100%K because the ink coverage would be 400% which is much too high and will cause the ink to spread and smear.

You may think that just using black ink is a good solution (so using 0%C, 0%M, 0%Y, 100%K) but this is not the case. Only using black ink to create a deep black result will in fact result in a grey tone. You should use a balanced CMYK value to create the best black that you can.

The black that the Coated FOGRA39 color profile uses is 91% Cyan, 79% Magenta, 62% Yellow and 97% Black. We advice you to use this value when creating black elements in your printed media artwork files.