It's probably dark because the normals are inverted. This can be verified by selecting your object and activating Model > show > normals. If the normals are inversed, then invert the object with Model > Effect > Inverse.
for an alternative to building halves and merging, you may want to try modelling using the sock method. That is, start with a cylinder and warp it so one end is the mouth and the other is the base of the neck. The advantage to this method is that you get very natural skin folding around the jaw line, throat, and face. It also keeps your head as one piece for quicker interaction. Eventually the eyes and ears can be added with a few extra pieces of geometry and blended texture mapping with Rendermap.
At first, the cylinder should have the minimal number of subdivisions (like 3) and new subdivisions should be added as you go when the model is tweaked as much as possible in the current state. If you start off with too much detail, you'll only be pushing points until you're blue in the face without gaining much. Sooooo, quick recap:
1) Get > primitive > Circle (choose NURBS or Bspline for example)
2) Rotate -90 degrees on X
3) Model > Effect > Freeze > Orientation.
4) Surface > Extrude. Use default values.
5) Select points at top and bend them over in X (forward towards default camera) until they reach where the mouth will be. Scale down to a near pinch (but not quite).
6) Select points at bottom of cylinder and reduce scale in half to form the base of the neck.
7) Select points and midsection of cylinder. rotate on X 45 degrees towards camera. this will form the cranium of the skull. Translate the individual points to start the sculpting process.
8) When points have been tweaked as much as possible to form a generic head, Use Effect > Subdivsion to add a row of points between the midsection and the mouth. reshape points to fit new head shape. Repeat until final head is constructed.
If you don't like socks, then ignore.
Matt
Matt Lind
Animator / Technical Director
Softimage certified instructor:
Softimage|3D
Softimage|XSI
speye_21@hotmail.com