A good Postcard printing company is one that has the resources to deliver high quality works either working in 4 over 4 color or HPs INDIGO System. The difference between one and the other is not only the amount of colors they work with (the first, as the name states, can only work with the CMYK color base, while the INDIGO can go up to 11 colors that can be mixed based on the PANTONE color matrix), this gives the customer the ability to choose what fits best for the intended job.