I'm trying to extract a shadow that's cast on a white background. I thought it would be as simple as changing the composite mode to Darken and then flattening the layer so only the shadow remains but that doesn't work, Darken only works if there's a layer beneath it.
This is the image I'm working with.
There's a box layer on top, behind it is the white background layer with the shadow on it.
Any suggestions on how I can get the shadow on transparency? Thanks!