Well, I am finally used to version 2.40 and the settings. I have been studying other people’s heads here and how they do skin, so here’s my millionth attempt at doing this again.
The skin seems rather good, but it looks to rough on the forehead (the front view on the top right gives the impression the skin is really rough there)
There also some small variations of color, as if the skin was freckled (but very lightlly freckled). I don’t know if someone could really have freckles all over his face (well, I met a girl like that once, but it was a skin desease %| ). Oh, well… as the freckles are not too visible, I like the looks it gives to the skin. 
I’m criticising small details, but the overall look is good 
(close ups are great for nit-picking :p)
I dunno if you wanted comments only on the skin or on the skin and teeth, but there color is strange. Grey? Maybe a more yellowish grey?
The skin looks like it’s as rough as sandpaper. Like 200 ply. And there’s some texture strecting under the mouth.
Rore & henrymop Thanks for the C&C, I agree that the skin is rough looking.
I used a photo of real skin and made a seamless pattern from it (for the Material). I enhanced the color too. But it looks too fake. I have a seperate bump map set with the NOR at 0.3, but I think it is the Material that make the skin rough.
I have found a few good skin tutorials, but they actually look like what I have - FAKE. The skin tutorials that do look good are for MAYA and Blender doesn’t work quite the same in YafRay as those programs. Well, maybe Blender can, but it is difficult to tweak the settings between renderings that take a long time to compile.
Have you checked out my head lately? I think I have a decent skin and I am still working on it. Areas that your face is lacking is discolorations, areas of blood concentraions (like the ears, nose, cheeks), underlying veins, texture needs to be finer, AO, faked SSS (can’t do this until blender supports multiple material layers since I’m working with vertice paint), and more variety of skin bumps. Skin is designed to stretch in every direction so the actual skin tends to look crackely and going in all directions. I think in smoother skin the crackels are just very very tiny, but they are there. I’m also thinking that a layer of yellowly fat under the skin when material layers comes out might help with skin color.
There was a procedural skin tutorial in one of the blender mags. Can’t remember exactly, but I think it was in blender man May issue… check it out. (If you haven’t.) I think it’s on katorlegaz.com .
Maybe add some specularity and reduce the repeat values at the texture(if you have set it to high)
This is too funny looking…
I just had to post this here. Experimenting with hair too.
You must not use the same material for the whole head. For good looking skin you have to use uv maps (note the plural). one for colour and one bumb map at least.
Look what Julian Jeremy Johnson-Mortimer does. http://www.3dtotal.com/team/Tutorials/julian_creating_character/julian_creating_character_01.asp
Doing all at once might be too much for the beginning, but it will give you some idea. Start with a colourmap and one bumbmap.
And once you did the unwrapping it’s fun to do… at least for me.
Here is another great tutorial on making realistic human-skin textures. It’s for Maya, but I think it’s also useful for blender.
@ daBoON: thanks, basically I was referring to that one, sent the wrong link… :-?
I like this one.
http://home.comcast.net/~dpattenden/hi_poly_tut.htm
Looks like a good base. You got to uv map the textures. When you use a color map dont turn it all the way up. Try a spec map at the lips and around the eyes. If you are trying for a procedural texture only check out one of the Orange builds with material nodes.
Hey, that’s a great tutorial!!! I have to apply that to BLENDER.
My rendering at the beginning of the post here, has UVmap for the skin ,and a UVmap for the NOR (bump map).