ColorTest allows you to check the surrounding light so you can locate the brightest light source: a chandelier, a lamp and a window. With this function you can also check if the card is empty or stored. The white surface is recognized as a very bright, which makes the tester thin squeaks. The ink is black, which makes squeak turns into a low murmur. White is mixed with the black, so tester specifically and irregularly buzzes. Ii allows you to recognize if two objects have the same design. ColoTest is a multifunctional and most professional device in a group of colors testers.