A calibration sheet is a tool that helps to ensure a printer is properly translating colors between formats and making efficient use of the ink. Printer calibration sheets help to ensure seamless color transitions between the appearance of images on the computer monitor and the output from the printer.
Calibration sheets typically look different across the various brands, but nearly all include multiple lines or bars of color that test out the numerous tonal changes the printer is capable of making. The specific methods for calibration vary between printer makes and models and depend on whether or not the printer has a scanner.
As of 2015, all computer monitors display color using the RGB format, which breaks down complex images into a series of red, green and blue pixels. However, the majority of color printers use the CMYK color format, which creates images using the colors cyan, magenta, yellow and key, also known as black.
If the printer has a scanner, it is possible to scan the test sheet and have the printer software automatically review the image and make adjustments to avoid bleeding or disruptions in the tonal shift. If there is no scanner, the owner must often adjust the ink distribution manually through the printer drivers or a separate printer management utility.