Hi Sergio,
That is some impressive piece of work. My only worry is the hard edge to the hair around the top of his head. He could be bald, in which case his head would be sharp edged. Then again, he has hair coming down onto his forehead which indicates he has hair. bewildere
You might be interested in having a look at this artist's work. She does oversize watercolour portraits and won a prestigious portrait competition in Australia last year.
http://www.cherryhood.com.au/
How long has it taken you to do this piece? Do you use powdered graphite, or graphite sticks or pencils?: