About Color
Light vs. Ink
There are two ways to make colors: you can mix light, or you can mix ink.Computer monitors make color by mixing light. For example, an even mix of red and green light, with no blue light, makes yellow light.
Printers make color by mixing ink. Ink works differently than light. A mix of red and green ink would make a muddy brown, not yellow.
It can be difficult, even impossible, to exactly match colors that use light with those that use ink. This means that colors that look good on screen may look different on paper. Your printer will do its best to match colors when you print, but it's not likely to be perfect.
RGB vs. CMYK
When your computer makes a color to display on your monitor, it uses the RGB color space. RGB colors are created by mixing red, green, and blue light. But when it's time to print, the CMYK color space is better, because it makes colors by mixing ink rather than light.Using the Color Picker
The Color Picker panel allows you to select colors in several different ways. Most ways, including the RGB Sliders, let you select RGB colors. This allows picking bright colors that look right on your display.Another way is to use the CMYK Sliders. These give you colors that will work well when printed on paper. You'll notice that CMYK colors can't be made as bright as some RGB colors. Your monitor will do its best to show CMYK colors properly on-screen, but again that won't always be possible.
If you plan to print on paper, then we strongly recommend using the Color Panel's CMYK sliders (or the Gray Scale Slider) instead of using any other of the Color Picker's options. You will get the best available color match between the screen and your printed cards.
If you plan to export for online use, then we strongly recommend using the Color Panel's RGB sliders (or the Gray Scale slider).
If you want to do both, then we can't really help you. You will have to experiment to find the colors that will look best both on paper and on screen.
Using Rich Text Markup
Rich text items can use markup commands to change color in the middle of a line of text. The markup language allows you to specify colors in several different ways. You will get the most accurate printed colors if you use the "cmyk" form.See Color in Rich Text Markup for details on specifying colors in rich text.