Can I make an alpha channel for a texture to be used as a specular map?

Unity Engine
1

Is there a way to do this, or shall i make another channel in my texture file in Photoshop, and then will unity use that channel automatically?

2

If you look at the built-in Unity shaders, the Specular ones use the A channel of the diffuse texture.
It depends what you mean by automatic.

3

I mean, if you have 4 channels in your texture, (RGBA), will the specular shader use the alpha channel if you have it?

4

From http://unity3d.com/support/documentation/Components/shader-NormalSpecular.html:

For more information on the other built-in shaders, specular and otherwise, check out http://unity3d.com/support/documentation/Components/Built-in%20Shader%20Guide.html

5

Cool, thanks- that’s all i needed to know.