In this Adobe Photoshop tutorial, we’re going to look at how to give waterfalls a silky smooth appearance, as if the photo was taken with a longer exposure which would normally require the use of a neutral density filter.
With your image open in Photoshop, grab your Lasso tool from the Tools palette
Then, with the Lasso tool selected, drag a selection around your waterfall. It doesn’t have to be surgically precise, but try not to stray too far from the edges of the waterfall:
With the waterfall selected, use the keyboard shortcut Ctrl+J (Win) / Command+J (Mac) to copy it onto its own layer above the Background layer. You won’t see anything happen in the Document Window, but if you look in the Layers palette, you’ll see the waterfall on a new layer: