11 hours ago, 7d2dMP said:
If you can save a 16bits PNG i think that you should work on this.
Verify that the grayscale decrease/increase is smooth on screen, try a smooth function inside your graphic software (or blur)
Yes I am saving 16 bit grayscale png, however it still doesn't work.
I have a guess: maybe unity by default converts png to 8 bit?