Lasers are increasingly used in the field of industry and displace conventional ways of surface treatment. One of the important purposes is decorative color marking of materials, because it is relatively quick and cheap. In this thesis we are dealing with finding optimal parameters for the formation of certain colors on the stainless steel and explain, why color occurs. Samples were marked with a laser system consisting of a nanosecond fiber laser, a scanning head with an F-theta lens having a focal length of 163mm, positioning system and a graphical user interface SCAPS SAMLight. Results were evaluated by using an optical microscope. Color marking was made on samples of stainless steel AISI 304. At the end of this thesis, we also used a laser to mark the color photography. By experimentation we were able to determine parameters for producing white and black marks as well as the following colors: pink, purple, orange, yellow, blue and green. We also examined, how laser parameters, such as average power, marking speed, pulse frequency, pulse duration and line separation distance influence on appearance of different colors. Additionally, we have shown that the angle of marking lines plays an important role in laser color marking.
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