Photoshop Tutorials: Create Silky Smooth Waterfalls

Step 4: Add A Layer Mask To The Waterfall Layer

The motion blur effect looks nice, but it needs a little cleaning up since the blur is extending outside the edges of the waterfall. We can clean it up easily using a layer mask. To do that, with the waterfall layer selected, click on the Add A Layer Mask icon at the bottom of the Layers palette:

This adds a layer mask to the layer, and you can see the layer mask thumbnail now in the Layers palette:

Step 5: Paint With Black On The Layer Mask To Clean Up The Blur Effect

Press D on your keyboard to quickly reset your Foreground and Background colors, so black becomes your Foreground color. Then grab your Brush tool from the Tools palette:

You can also press B on your keyboard to quickly select it.

Then, with black as your foreground color, which is the color your brush paints with, paint away any unwanted blurred areas around the waterfall, most of which will be along the top and bottom. Use a soft-edged brush for best results. You can resize your brush as needed using the left and right bracket keys ([ and ]) on your keyboard, and you can soften or harden the brush by holding down the Shift key and using the bracket keys. With the Shift key down, pressing the left bracket key softens the brush edge, and pressing the right bracket key hardens it. Paint over any unwanted blurred areas. Since we're using a layer mask, any areas you paint over with black will disappear.

Here's my image after painting along the top and bottom of the waterfall to remove the blur from those areas:

In most cases, you could stop here and your effect would be complete, but in my case, there's a bit of a problem. The water is rushing so quickly and powerfully over the edge that it's not falling straight down. It's actually falling on a bit of a curve. We can't create curved blurs with the Motion Blur filter, but if you're using Photoshop CS2 or later, we can still add a curve quite easily, which I'll do next.