We're going to create a hair texture from scratch with Photoshop using brushes and different filters for the brushes, all in just a few easy steps. For the purposes of this demonstration, I'll be using a hair texture from Loch & Sil's Sexy Female Hair Styles found on Morrowind Summit, if you need to practice with the same texture as I'm using.
NOTE: You'll want to have the model in some kind of model viewer to tweak the texture's flow with the polygons as you go. Have it set up with the model using the new texture first, before you start working the hair texture. This way you can see it while you work.
1. Open your UVW map of your hair model or existing texture you wish to redo (hopefully you've gotten this far, we'll assume you have or you wouldn't be reading this) and maximize it to the workspace on-screen. Fig. 1
2. Use the magic wand tool to select all of the black background, then invert the selection to select the actual textured area. Fig. 2
3. Now pick your base color. Can be anything you desire, even a color not normally for hair...this is your call (I chose brown for this tutorial). Hit Alt+Backspace to fill the selected areas with this color. You now have the base for the texture. Fig. 3
4. Now with your color picker, pick a slightly lighter color than the one you have for the base. Click the L (See Fig. 4) to pick the 'level' which is the best for monochrome hair colors. If you like Bozo rainbow colors, then just go nuts and pick whatever you like. Fig. 4
You can 'lowlight' or shade in the darker direction by using the 'color burn' and the 'linear burn' modes with the paintbrush...useful before the highlights so you get a nice array of tones, and it looks less flat. You'd do this before you do the highlights but in the same way, and with a darker color than your base. Then go over it with highlights.
5. Now the work begins. Click the paintbrush tool in the tools palette, then go to the brush picker and pick a small, hard brush (between 2-8 works for this particular texture). Then you have to set the brush's 'mode' to either 'color dodge' or 'linear dodge' so that it will look like it is being painted to the texture rather than just pasted over. You can also set the 'flow' to a lower number, but I find that breaks up the lines too much for this particular job. Also set the opacity to a low number, around 3-6%, so you can go slowly and work the texture into shape. Fig. 5
6. Make a new layer, a transparent one to actually paint on. This will help you keep from having to do the previous steps all over again if you mess up this part at all. Just delete the layer and start this part again if you have to. Keeping in mind the flow of the model's hair, now you paint in long, flowing strokes..sort of like brushing your hair. Go from start to finish without stopping. Dont cover the base color completely, just make even lines along the flow (See Fig. 6) so that the base color is still shown, but highlighted by the lighter color you've chosen. You still have the textured part selected, so running outside the selection wont hurt anything. Just get a basic flow going, and go from top to bottom, across until you finish. You can flatten the image once you're satisfied with it, to convserve HD space. Fig. 6
7. Make another new transparent layer, and open the color picker again. This time you pick an even lighter color, for lighter highlights. Repeat the process in step 6, taking care not to completely cover up the first highlight you made...only highlight that color, like you did to the base color before. Again, you can flatten the image once you're satisfied with it, to convserve HD space. Fig. 7
8. Repeat the same process yet again, using an even lighter color. Each lighter color you go, use it ever more sparigly as to not cover up the previous colors. Pick a smaller brush size if you're having problems keeping the previous colors intact. All the while keep an eye on the model, and look how the flow of the hair goes with it...try to keep it from crossing the flow as much as you can...digital medium is pretty forgiving, but there are boundaries. If you want more highlights or that 'shine' you pretty ladies get in the sun, just highlight certain areas (the rule of going the full length of the texture dsoes not apply to the lightest colors, you can do this and it will look good). Fig. 8
9. Now once you're done with the initial colors and texture, you can select certain parts to have broader highlights. Just use the polygonal lasso tool to select the dome of the head area and feather it accordingly, then bring up the levels of any layer you have to highlight that part. Fig. 9
10. That's the basics. I'm no expert as you can tell by the sloppy job in the pictures, but that was just for the tutorial. I'm sure with practice you could make some slick and better textures with some practice. But this is basically how you do it. You can do this with any hair texture.
Note: This tutorial is a companion piece to the Face Texturing for Morrowind tutorial.