Every logo is specifically designed to identify an organization. Many logos are generally composed of an icon and logotype. Both must be able to stand on there own as part of the visual identity. Usage guidelines like this specify how the logo and its colors are to be used to create a foundation for visual unity, impact and consistency when used in print, broadcast and digital media.
To retain the integrity of the logo it's vital to retain an area around the logo. The space helps to provide a visual priority.
A guideline also gives examples of how the logo should be applied in many different applications. Full color (3-colors), black and white, as well as reversed out from both a branded spot color (1-color) or another solid background. Logos should avoid being placed over a patterned background at all costs.
It's always best to start with a standardized color system like Pantone. Although it is impossible at this point to have extremely tight control over colors online, it does allow you to have much higher control over anything that is printed, embroidered, or painted.
This guideline tells your printer what pantone colors they should use when printing spot colors as well as the process build that should be used when a four color process brochure or label.
When none of your spot colors are available I generally suggest printing the logo in black.
When possible use black ink when printing a one-color logo. If black ink is not available, you may print this logo in the ink required, although it damages the consistency of the logo.