Shadow Filter Sharpen works as expected for values of 0 and higher, sharpening the shadow with higher values:
However when using negative values the shadows get inverted:
I would expect the following behaviour:
- Negative sharpening blurs the shadow
- If for technical reasons blurring is not possible, the value should be clamped to positive values
Tested in 4.6.1 and 4.7 preview 7, both give the same results.