Bumpmap from grayscale in 2.8 I purchased a model with source Blender files from TurboSquid and am attempting to make some changes to the textures. The .blend file uses the Cycles renderer, and the mesh has a "Principled BSDF" material with Base Color texture and Normal Map texture.

The normal map uses a color normal map file. I am trying to replace this with a grayscale bump map which I find easier to edit. Using the internal renderer in Blender 2.79 and earlier, I would add an Image texture slot, select the grayscale image, check the "Normal" influence box, and check the "RGB to intensity" checkbox to make the grayscale image suitable as a bump map.

In Blender 2.8 using Cycles and Principled BSDF, there doesn't seem to be an equivalent to the "RGB to intensity" checkbox. I can't figure out any way to achieve this. Additionally, the Principled BSDF seems to only be editable in the Properties editor, and I can't figure out any way to convert it to nodes (the "Use Nodes" button isn't showing). 

How can I use a grayscale bump map instead of a color bump map in 2.8?
Whoops! Turns out the material was already using nodes, I was just looking in the wrong place. I'd been looking for the material nodes in the "Texture Node Editor" view, but where they were actually located was in the "Shader Editor" view. From there, I was able to follow the instructions from the first answer to this question: Bump Map applique in Blender 2.8?