There are several methods of coloured anodic coating for aluminum profile, and the oxide film of industrialization technology can be divided into the following three categories.      

(1) Integral-coloured anodic coating. Japan is also known as the natural hair color film or an electrolytic hair color film. Here is sometimes subdivided into natural hair color film and electrolytic hair color film. Natural hair color refers to the anode oxidation process so that the aluminum profile added components (Si, Fe, Mn, etc.) oxidation, and the occurrence of oxidation film coloring, such as Al-Si alloy sulfate anodic coating; For example, anode oxidation in electrolytes with organic acids or inorganic salts is represented by the Kalcolor method (sulfate and sulfonic salicylic acid) and Duranodic (sulfuric acid and phthalates).      

(2) Tinted Films.Based on a transparent anode oxide film with an electrolytic sulphate, the oxide film is dyed with inorganic pigments or organic dyes.       

(3) Electro-coloured anodic coating. Based on the transparent anode oxidation of one electrolytic sulfate, the anodic coating is electrolysised with DC or AC in a solution containing metal salts, also known as the secondary electrolytic membrane in Japan. It means that anode oxidation is called an electrolysis, and electrolysis coloring is called secondary electrolysis. The industrialization techniques of representative electrolytic coloring are Asada (Ni Salt AC Coloring), Anolok and Sallox (both of which are Sn salt AC coloring methods), residential and Yunicol methods (Ni salt "DC" coloring and "DC" pulse coloring). In recent years in the industry began to be popularized multi-color technology, can be in an electrolytic coloring tank to get a variety of colors. This is a new electrolytic coloring method that uses interferometry effect, which is also called three electrolysis in Japan because of the addition of electrolysis adjustment before electrolysis coloring.