I realise this is an old thread, but it is still as relevant today as it was when the very first post here was made. Many hairs are still textured with painted on highlights and removing them can be a pain. Bagginsbill's method was a great revelation to me and extremely useful. Thanks very much for this simple trick, I doubt I would have found it on my own.

The shaders presented however, don't give such good results as the shading method I have found. I get better results and the shader is simpler so it renders faster.

My method does not need any elaborate shader nodes. It produces correct highlights that look like those on real hair, yet it uses only image map nodes. I don't even use the anisotropic shader for the highlights, but the normal specular slot. Because there are no elaborate node setups it renders quickly.

Here are two examples — please ignore the effects of the Renderosity system rescaling the images. The best way to view these it by using your browser's view image facility to view them at their native size. This is Radiant Jaguar Hair on Victoria 4 with my shader and textures — yes, you need more than one texture map to get this effect but they aren't hard to prepare once you have the greyscale map obtained using the Bagginsbill method in Photoshop:

I will post again once I have prepared the images for a clear explanation of how this works.