Expand visible tonal detail
Shadow recovery lifts dark regions more than midtones. Highlight compression lowers bright regions, while Local detail compares each pixel with small and large neighborhood averages. That produces the textured contrast associated with tone-mapped HDR images from a single exposure.
This is not exposure merging. A single JPEG cannot reveal information that was clipped when the camera recorded it. The effect works with the tonal differences still present in the file.
Two radii, one texture control
The detail pass runs at two neighborhood sizes tied to the image dimensions: a small radius that sharpens fine texture and a large one that separates broad tonal regions. Raising Local detail scales both together. That is why the control adds punch to brickwork and clouds at the same time, and also why overdriving it affects every scale at once.
Because the radii are relative, the preview and the full-resolution export show the same amount of texture emphasis.
Example: backlit street scene
A photo with a bright sky and a dark street is the standard case. Set Highlight compression near 50 to bring the sky back, Shadow recovery near 60 to open the buildings, and only then add Local detail until surfaces feel dimensional, usually 40 to 60. Watching the sky boundary while raising detail shows exactly when halos start.
Skin tolerates far less: for portraits, keep Local detail under 30 or pores and blemishes take on the crunchy over-processed look that gave HDR a bad name.
Avoid hard tone mapping
Work tone first, texture second. High detail on skies, walls, or skin creates halos and emphasizes compression artifacts. Saturation above 100% strengthens the color left after tone mapping; lower it when recovered shadows turn unexpectedly colorful. Flip the Show before toggle often, because eyes adapt to the processed image within seconds and the grade drifts stronger than intended.