I'm just posting this so I can post the pic. This is just an example of how you should set up your nodes. I used a multiply on the MixRGB node because I often transfer dark ridges this way, but I don't know what your image looks like, so I can't tell what the values are doing. If you need the lights, use Lighten or Add. Or disregard all of that, and use whatever looks best. The main point is that you must convert the sRGB image into black and white before introducing to the Bump Node.

I didn't show it here, but I also often mix the procedural component of my textures heavily with white (or black sometime depending on the need) using another MixRGB node to easily soften the contrast (strength) before mixing it with the others. I find the default values are often too strong, and look unrealistic.