first likeness sculpt done in zbrush and for texturing i used substance painter .All the texture are handpainted in substance painter . I did not use projection for that.
for rendering i used marmoset its really cool software for global ilumination
i learning those technique texturing from saurabh jethani ( https://www.artstation.com/jethani ) and for sculpting technique i follow frank tzeng (https://www.artstation.com/frank_tzeng ) . These are great artist checkout there works man hats off to them

