Photoshop indeed. I wanted to finish them as a cohesive set, so I just applied
the exact same processing to each of the four images. Not a lot done here to
be honest. Very briefly…
Duplicate layer, apply high pass filter at 50 pixels, set to soft light…
Add a solid black layer, set to colour, opacity 20%…
My usual sharpening using calculations to select the darkest edges for USM…
I should really have reduced the opacity of the high pass layer too; I processed these
at night, but in the cold light of day there are some haloes that bother me…