This tutorial will show you how to do a clow wave. This effect has alot of room for tweaking and playing with things, so it's a pretty fun effect.
1. First we need to open a new file about 400x400
2. Press "D" to reset the forground and background colors
3. Goto Filter > Render > Clouds. Then Filter > Render > Difference Clouds
4. Now we need to invert the image. Press CTRL I to invert or go to Image > Adjustments > Invert . Now go to Image > Adjustments > Levels or ctrl L and use these settings
5. Now the fun part. Go to Filter>Distort>Wave and use these settings. These settings can be played with so experiment
6. Your finished you should have something like this.
I know this effect doesn't look pretty but with some experimentation and blending and such it gives nice smooth effect. Here's some examples of this effect.







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