Now the 3D part is over, everything coming after is the result of a long post-production in Photoshop.

I created the colour map directly on the rendered model in several passes; in picture 9, you can see two different passes, one obtained with brushes and the other one by means of a gradient. Then, the result was mixed with a dirt layer obtained, in its turn, by several textures welded together by means of gray scale masks (picture 10)

I multiplied, therefore, a colour pass with lighting and occlusion ones (previously obtained) (picture 11);

such result was multiplied with an image base lighting pass obtained through several light sources generated by a HDRI map (picture 12)

The last picture you see is the final result obtained by colour correction and contrast curves (picture 13).