COLOR SPACE
There are two types of color spaces in digital printing:
                            RGB  and  CMYK

(RED/GREEN/BLUE) and (CYAN/MAGENTA/YELLOW/BLACK)

In the world of digital printing, all image files are created in an RGB color space (scans, digital photographs, websites, and monitors). Even though scanners work with RGB, the images may be saved out as CMYK.

The advantage of using RGB files is that you only have 3 channels. This means you have 75% of the information as compared to the CMYK file, which has 4 channels. When dealing with files which exceed one Gigabyte, one less channel can make a difference in file size. This is particularly true if your computer does not have enough RAM, or processor speed, to handle a larger file size.  When you need to upload a large file to an FTP site, it can be advantageous to have 25% less file space. RGB is generally the preferred file space.

CMYK is the color space of most inkjet printers. Some print providers depend on their inkjet printer RIP to convert an RGB file to CMYK file. You should speak with your graphics provider to see what kind of color space they require for their output device. Some inkjet printers have additional variances (light magenta, light black, light cyan) to increase their dynamic range. However, inkjet printers are not always CMYK. Some inkjet providers have optimized their RIP to accept RGB files. They let the RIP do the conversion to CMYK, which can give the best results.

Photo output printers, like the Durst Lambda and the Lightjet, are also known as laser imagers. These devices typically accept RGB files. You should not provide them with a CMYK file. The RIP will convert that CMYK furnished file into an RGB file, which will truncate the colors.

In summary, it is key to talk directly to your print provider and understand their requirements when deciding which output device to use.  For more information on file preparation for large digital printing, click download.

photo credit: resumebrae.com