Another kind of color that we haven't already dealt with much is spot color. In Scribus, creating and using a spot color is really easy. To create a spot color, just do as you would do for any other color and select the Is Spot Color checkbox. If you use a color from a reference catalog like Pantone or other, the name of the color you define in Scribus should be the same as the name in the catalog.
In the color list, spot colors will be identified by a red circle and you can apply it as you would do for any other color.
So then what's the difference with other colors? When printing colors in CMYK, all the colors will be a composite of those primaries (we call that process colors). So printing a color document will necessarily need those four colors and the plates (in Offset) that go with it. There are few issues with this process:
You can't be sure you'll get the exact color you want at the end. Primaries will give a different result depending on the shapes, angle, or frequency...