What color is neutral for a bump map noise?

[nullbio]

I'm using a noise as a bump map with a clamp. I want it to be a indent only, so I'm trying to figure out what values to use for my clamp.

Is grey neutral and black negative? So I would do 0 - 0.5 in my clamp to do only negative bump?

[frankmci]

As I understand it, bump maps don't really have a neutral or zero point, unlike displacement maps. They are closer to the way normal maps function, where the value of every pixel is really only relative to the values of the adjacent pixels, for rendering purposes. So if you are using 256 levels of gray, you might as well treat white as your zero, to give you the most delta resolution to work with.

[nullbio]

How am I supposed to control bump height then? What if I only want a really shallow (and indented) amount of bump, with no positive bump, for example?

[jayroth2020]

Add a gradient node between the source node (RGBSpectrum node, noise, etc.) and the bump port. Then adjust the slider value of the gradient.