What part number?

3626

The way you can figure this out is by painting the different blocks of the UV map different colors... then upload that and see where the different colors fall. Or you can upload a UV checker image to do something similar. I use this one by fisholith on Deviant Art:

Make a custom part and upload the UV checker image as your color texture. Now look and see what color is on the front of your part. I did this for 3626 uv1 below. You can see that the uv map wraps around the minifigure's head with a seam where the minifig's left ear would be. So the right half of the map does the front of the head and the left side of the map does the back of the head. On this map, the center of the front face is the 3/4 point from the left.