With proper color calibration, computer displays can reasonably simulate printing. This process is called soft proofing since color approval is not based upon an actual hard copy. Of course, it is of little value to only calibrate the display but not the printer and visa versa. Color calibration is an end-to-end color management solution -- from input to editing and output.
Even with ColorSync a part of the Mac OS, color matching is not automatic. The software used for viewing color must support color profiles. These profiles should also be embedded within the document's images. A common mistake made by users is that the Color Management option is not enabled in each required application. The Adobe Creative Suite supports color management within Photoshop, InDesign, Illustrator, and Acrobat. Often the latter is left out and PDFs are saved without embedded profiles. Including ICC profiles increases file size. But even if profiles are included, it will not be apparent within Acrobat unless Color Management is activated.
When Color Management is enabled, the user is prompted to define a default RGB and CMYK color space. Within a print workflow, Reactive Imaging primarily uses "Adobe RGB (1998)" for the former and "U.S. Sheetfed Coated v2" as the latter. Note that this differs from the default website sRGB color space workflow. If the latter is your preference, be certain to include ICC profiles when saving images. For Adobe CS3, color management settings in Adobe Bridge are synchronized in all supported Adobe applications. Color profiles for papers are available to help artist visualize how varying gamuts affect image appearance within Photoshop. Refer to the documentation provided with your software to learn more about managing color.
For critical color, is more economical to purchase a quarter-size proof than multiple full-size banners. Customers can also group key images from multiple posters together in one sample file.