Attached is a step by step for creating mist:
1.create a new layer called mist and paint on with a white brush the extent of the mist
2.add a motion blur horizontally
3.add a motion blur vertically
4.duplicate the mist layer
5.use filter render/difference clouds
6.the second last image shows the difference clouds layer and the mist layer turned on
7.the last image shows only the difference layer turned on.
TIP:If you have added vegetation entourage by layers you can move the mist layer up or down to show the mist disappearing behind some elements and covering others.


