Adjusting the color and contrast on a flat panel TV that has been in use approximately 100 hours. In order to display content as originally intended, separate adjustments must be made for each source, typically the cable box and the DVD or Blu-ray player. Calibration Discs and ISF Certification Calibration DVDs are widely available for consumers and professionals. By following the instructions on the disc, adjustments can be made. However, the TV's setup menus can be complicated, and the wrong adjustment can render the TV inoperable. Consumers often opt for a professional calibration by people who have been certified by the Imaging Science Foundation (ISF). They come into the home with analyzer and test pattern equipment and are able to make fine adjustments that the user cannot. See color calibration.