Colorbar is a graphic used in the printing process to maintain the correct amount of ink and ink density on different substrates for 4 Color printing and other critical color types of printing. Using a Spectrodensitometer (a device used to read color and Ink densities on different substrates) a pressman checks the ink balances by reading the color bar. This allows for good quality and color appearance and also allows the pressman to maintain or correct the printed piece due to color shifting.