Facing corrections


Air-Valve Autobot!
I'm planning the execution of my pinup for the contest , I'm doing a lot of practice because I never paint portraits before and in my reference the face turn out small , increasing the difficult for me.
It would be great to paint a lot of faces , choose the better , cut it and past it in the canvas , but is not the better option LOL
I will probably have to make several corrections or repaint it so I will paint it last , masking the rest of the artwork

There are any advice that you can give me to prepare the matted for that or some useful techniques ?
Erasing can be a problem in matted , and cover in white can give me blue shift wich is worst
Yep what andy said and also, corrections in size and proportion can be taken care of in the drawing stages. It's a whole lot easier to correct those then than it is to correct them after they've been painted.
You could enlarge your image by posterizing it or projecting it onto your surface. Or go totally old school (and I mean OLD) by doing the grid system.
Print out your reference, a few times, on one copy, draw your grid squares. Now on your canvas or whatever you're painting on, draw a larger grid lightly, so it can be erased later. Copy what's in each individual square to it's corresponding larger square on your canvas. Draw exactly what you see in each square. It doesn't have to be a fully rendered drawing but outlines of the shapes of the light and dark areas. A sort of map, if you will.
After you've copied all your squares you can erase the extra lines and start painting.