I increased the contrast and blurred it again, and the stairstepping was much reduced. I also cropped it, so the repeats was quite off. I would try maximizing/normalizing the channel output in substance painter to give it the full 0-1 range rather than the 0.878-1 range I found with the latest image.
I don’t know about other software, maybe they have a blurring filter applied automatically? I know max had it back in the day when I used it last (15-20 years ago?), and it’s something I’ve missed in Blender - on any output (which only has image pixel interpolation).
Unless you have other information in the texture that varies across that scale (i.e. a diffuse channel that varies in brightness), I would generate less identical tiles to spread the gradient across. So brightness 0-1 over 1000 pixels instead of 0.878-1 over 50 pixels and multiply the tiling in blender instead.
Update: I managed to get things working. I never got the ridges to completely go away, but I managed to get it to a point where I could get the detail needed out of the textures from the distance I’ll be viewing them at. (The mattress will be in a bedroom.)
The biggest help was actually just multiplying an Ambient Occlusion pass over the render. This gave more perceived depth to the stitched areas. Thanks for the help I learned a ton.
Thanks so much! Adding a Color Ramp node set to “Ease” (without adjusting any of the color flags) between my 16-bit image and the Height input of the Bump Map node was enough to completely erase the stair-stepping.
