The black and white image was flipped horizontally and printed on a sheet of translucent vellum on a jet printer, so that it could be colored with alcohol-based markers from the back without dissolving the black illustration outline. This is a view of the back of the sheet of vellum where the markers were applied.
The marker colored image was scanned and flipped back to its original position with Photoshop. Thus the finished image of the Steampunk mecha was colored with Copic Sketch markers and Faber Castell Pitt Artist brush pens from the back and outlined with a 0.35 mm multiliner on the front of the sheet of translucent vellum.
Added another layer of marker coloring with the Faber-Castell Pitt Artist Pens on the front of the vellum illustration to make the mecha's colors a little brighter and better defined.