Here is some interesting information about the printers used at one of our production centers: Full color pieces are printed CMYK (Cyan, Magenta, Yellow and Black) on an Indigo Digital Offset press. Files are printed at an 812 dpi using liquid electro inks, not toner. The Indigo produces the best color quality of any digital press or copier currently on the market and runs at a speed of 1,000 12 x 18 full color two-sided sheets per hour.

Coated GRACol 2006 (ISO 12647-2:2004) 

   A transparent background is invisible to the human eye. If you drag an image with a transparent background onto your desktop, you will be able to see your wallpaper behind the image instead of a background. Transparent backgrounds are helpful during the design process, but printers often have trouble converting them into viable print files. Images with transparent backgrounds will print distorted or entire jobs will error and not print at all.