For the Specular Colour map, I used the Diffuse map and then desaturated it in Photoshop and made a few adjustments to the Levels. For the Specular map I took the desaturated Diffuse map again and used it as a base for my new map. In ZBrush I painted the changes that I wanted. For a more concentrated Specular I used the Secondary Specular of the Fast Skin Shader. To do the map, I used the Primary Specular map as a base and painted the changes in ZBrush with a few touches to the Levels in Photoshop.
From the high poly model (SubDiv level 7) in ZBrush, I produced a Normal map of the finest details of the model, which I applied to the medium model (SubDiv level 5).
For the skin material I used Fast Skin shader of Mental Ray which works really well (Fig.07)! To set the shader, I turned off the effects of Sub Surface Scattering. First I set the weight of the Diffuse, and after that I adjusted each layer individually of the shader until all worked well together. To control the area of effects of the SSS, I painted the maps in ZBrush and made some final touches in Photoshop (Fig.08).
Lighting & Rendering
I used Mental Ray in XSI to generate the final render. As I used the high poly model imported directly from ZBrush (Fig.09), I also imported a low loly version of the model (SubDiv level 1) to optimise the render tests (Fig.10).
The lighting was a standard 3-point setup using Area lights. The fill and key lights were white, and a blue tone was used for the back lights (Fig.11).
Finally, I generated an Ambient Occlusion pass (Fig.12), which was very useful in order to increase the sense of volume in the final image. In Photoshop, I joined the Beauty pass into the Occlusion pass leaving it as a top layer, and set the blending mode to Multiply. I decreased the opacity of the layer slightly to control the intensity of the shadows generated by the Ambient Occlusion.
This was my first attempt to make a complete character. I learned a lot during the whole process, mainly with regards to the textures and shaders for the skin. I'm happy with the final result and, most importantly, I had a lot of fun in the whole process - especially in the modelling stage! I would like to thank a friend, Diego Maia, who helped me a lot with valuable tips throughout the process.
That's all folks!