What this tutorial from Tuts+ teaches you to make:
I didn’t have the time today to find a portrait to apply it too, so I decided to do the overlay on the Silhouette building in Midtown, Atlanta. I took the photo back in May when I did a photo tour with my brother around Midtown. This is the original photo:
These are my rainbow overlays. Basically, the tutorial teaches you how to create your own color swatches and make a gradient with them. Which one do you like better?