The color system used in professional printing to print brochures, which is called "Process" or "CMYK" color printing, does not have the ability to create certain rich/vibrant shades of blue, greens, purples...and other colors. Colors like "Royal Blue" will actually print out much darker if you try to use this color in your brochure. This misunderstanding about the limitations of full-color process printing is by far the biggest issue/problem that car arise between you and the printer/designer. Be sure you understand that you will not be able to duplicate rich, vibrant colors in your brochure.See graphic below for the problem colors.

Examples of colors which cannot be correctly reproduced in Process Color Printing
Brochure proof as viewed on your computer monitor	Brochure as it might look when actually printed out

The bottom line: Your computer monitor can product rich, vibrant colors. The system used in professional printing cannot. If you view a proof for a brochure that is created using rich/vibrant colors, the colors will appear correctly on your computer monitor, as viewed in the sample at top-left. Yet, when it comes time to have this printed professionally, you'll be in for an unpleasant surprise. Your rich/vibrant colors have printed out much darker than you think, possibly created the need for an expensive reprint of your brochure

Sidenotes: It is not impossible to have these vibrant colors used in your brochure. To do this, a different color system would have to be used to print the brochures. This is called the Pantone color system. The downside to this system is that you will most likely not be able to print image/picture in full-color, but rather in grayscale.