Hi, asked this elsewhere and no joy so I thought I would ask in a place where the intelligent people hang out ...... ;) 

Is there anyway of changing multiple shaders at the same time ? I would like to take all the existing shaders in an existing scene and change some shader parameters in them with one fell swoop.

I have a vague idea of the use of a reference shader but that would mean changing all the shaders to access that reference shader? 

More detailed: I would like to take the shader textures and add an operator , new source 2 and specify the blender . 

I could save the scene with internal shaders, then save the scene with external shaders so all the textures are in one folder, then batch process them in photoshop, but I hoped there was a easier way.

thanks for any answers ;)