Cycles material appears black at render: RGB Curves

Hello.

blender 2.70

I have a small problem with setting up complex textures; on certain attempts the material turns black (null).

It’s the same regardless of the setup, so I will use a simplified example:

Tex Coordinates node ------- image tex ----------- Shader type ---------- material output

The upper example works fine as long as I don’t put anything other than a shader between the last two nodes - upon which the material in rendered view turns black. I am unsure whether this is normal; I thought you could tweak the material from anywhere in the pipeline? Is there a setting that makes it so?

One example is RGB curves or mix rgb. I can not use them to create more complex textures.

Use the RGB node or any other node between the image texture and the shader, and then it will affect your input going to the output if that makes sense - the output node is looking for a shader or mix/add shader, nothing else.