01 - Crate A New Document, Any Size, Black Background
02 - Select The Bucket Fill And Change It To Gradient Fill
03 - (Holding Shit) Click, Drag The Cursor From Left To Right Horizontally And Let Go
04 - Filter > Render > Difference Clouds
05 - Invert (ctrl + I)
06 - Image > Adjust > Levels, And Drag The Middle Arrow All The Way Right
07 - Create A New Layer
08 - Fill With A Color Of Your Choice
09 - Double Click On The Layer And Select The Blending Mode As Overlay Or Multiply
10 - Your Done!
By DJ_Durst