A new method for colors characterization of colored stainless steel using CIE and Munsell color systems

• Colors of stainless steel are characterized by CIE and Munsell color systems.
• Moving of peaks on reflectance curves causing cyclically changing of hue.
• The amplitude of reflectance curves influences the saturation.
• The CIE coordinate curve of colors counterclockwise and cyclically changes.

It is important to establish an accurate and comprehensive method of characterizing colors of colored stainless steel and understand the changing mechanism and the regularity of colors for the research, production and application of colored stainless steel. In this work, the method which combines reflectance-wavelength with both CIE and Munsell color systems is studied, the changing regularity of hue, brightness and saturation with increasing coloring potential differences is investigated, and the mechanism of color changing is discussed. The results show that by using this method the colors of colored stainless steel can be accurately and comprehensively characterized; with coloring potential differences and colored film thickness increasing, the peaks and troughs of the reflectance curves in visible region move toward long wave, causing the cyclically changing of hue and brightness; the amplitude of reflectance curves increases, resulting in growing of the saturation; the CIE 1931 coordinate curve of colors counterclockwise and cyclically changes around the equal energy light spot.