The equipment picture is processed to look good with the kind of silver color on the coloring page.

With PS software to deal with, the general process is: the first blur, and some of the miscellaneous colors (such as spots, rust points, etc.) to deal with clean; and then add highlights, dark shadows, so that the contrast increased; and then the corners of the processing clear, and finally add some texture on the OK.

Here in a few words is impossible to say clearly, it is best to find an example tutorial to see.

Satisfied with the adoption, please respect the labor of others!