Hello,
I have been working on this portrait for past few months, for the model i have just used one of my old heads,and changed few things.base textures were painted in zbrush 3.1 with the help of projection master and polypainting,later on i used lot of maxon's bodypaint and photoshop to paint some more details on the textures,so it was back and forth process between zbrush 3.1 and bodypaint for all texture maps.displacement and bump maps were extracted from zbrush 3.1.

For rendering I am using Mentalray with imagebased lighting .I am using MISSS Fast skin shader for the characters skin and Eyes.Eyebrows were made in maya painteffects .

For the modeling base mesh in Maya, Mudbox and Zbrush for all sculpting and detailing.Finally the image was composited in Photoshop.

You can see lot of WIP images on my website :
www.salunke-mayuresh.com

Thanks.
Mayuresh