How can I add displacement to part of a material in Cycles? I made a mixed texture on cycles, that has a image texture as color, and a layer weight for the 'border' effects. Now I want to use the same image as bump, but I want to know the correct configuration/node order to do that.
To have a good control over a bump value add to your existing nodes set a Mix RGB node (Add--> Color-->Mix RGB), set its type to Multiply and the Color 1 to pure white. Connect it to other ones as shown below.


Now changing a factor of the node  will result in a different amount of bumpiness.