Displacement Map Issues

We’re trying to use displacement maps to recreate the rough masonry in this scan of the Vista House in the Columbia River Gorge:

 

We’re having two issues:

  1. As you can see from the scan image above, in most places the whitest areas are neither the high points nor the low points: most of those sharp lines are some kind of glitch (except where they are near edges). Changing the reprojection distance does not seem to help.

2)  In the middle of widest panel, about 1/3 from the top of the image, there are two vertical seams where the mapping shifts

it all looks fine in checkerboard view from both 3DS Max generated UVs and from RCs unrwap, but both generate that vertical seam in the displacement map.

  1. The output file formats for the displacement layers seem off.  Internally, the displacement layer reports as a 32-bit gray image, but the options for saving the layer (with FBX output) are EXR, WDP and JXR.  I’ve never heard of the last two. The default 128 bit RGBA (float) EXR which in in 8K format generates a 750MB file!  There is no 32 bpp gray EXR option - the closest might be 96 bpp RGB…  Isn’t there something closer?  (16 bpp grayscale PNG would be fine for most of our needs, but PNG is not an option for the displacement layer)