This page provides information on the Color to Bump Map.
VRayColor2Bump is a V-Ray utility node that converts any RGB texture into a bump map. VRayColor2Bump is best used within a texture network that does not support bump mapping (e.g. a bump map going through color correction). VRayColor2Bump is slower to calculate because it needs to evaluate the texture at multiple points, but it can be used within any texture shading network. Directly plugging a bump map into the network is faster and should be used whenever possible, leaving the use of VRayColor2Bump for times when other options are not possible.
Map – A slot to load the map that you want to convert to a bump map.
Height – A multiplier for the height of the bump effect. This basically makes the map brighter or darker.
Bump delta scale – Controls the softness/sharpness of the bump effect. Lower values generate sharper transitions in the bump effect while higher values generate a softer looking bump effect.