Screen and printer calibration
Another important technique for ensuring that what you see onscreen is accurate is to calibrate your monitor with a hardware calibration device.
These third-party sensors plug into the USB outlet on the computer and hang over the screen. Run the associated software and the sensor will determine whether the RGB colors displayed onscreen really are 100% red, green, blue, white, gray, and black. If the screen is different to the known value for these colors, the software adjusts the brightness and color to make it display correctly. This is a far more accurate method of color management than using the human eye to gauge the settings. As a general rule, screens need calibrating every six months or so, especially if they are used a lot.