Previously, Gimp 2.8 and earlier used a dialog with the familiar "radius, amount, threshold" parameters as described at Unsharp mask - what do the parameters do?, like this:
But in Gimp 2.10, we instead have this:
with "Standard Deviation" and "Scale".
The old dialog has Radius capped at 500 (useful for local contrast on high-megapixel images) and Amount capped at 10.00 (useful only for identifying where halos and artifacts are going to happen and then backing way, way down.) The new dialog has both new parameters capped at 300 if you type the number, but the sliders are non-linear and if you click with the mouse as close to the right as you can go without hitting the arrows, you get something around Standard Deviation of 40 and Scale of 10.
Threshold is to avoid sharpening noise; that's just gone, as far as I can tell.
How do the new parameters relate to the "classic" terminology?
I generally use the filter in three different ways:
- Very small (0.3 or so) radius, relatively high amount (0.5 to 1.0) for "clarity"
- Small (3 to 5) radius for edge sharpening with low amount (0.05-0.12), depending on image content and viewing size
- Very large radius (100 or 200) with low amount (0.05 to 0.10) for local contrast enhancement
How can I do these things with the new tool? I searched the Gimp mailing lists, but the results I got back are very mathy and not directly practical.