Trying out @5tu's Plastic Bullet app
I also downloaded Red Giant's "Plastic Bullet" photo manipulation app for iPhone. Unlike Hipstamatic, Plastic Bullet allows you to applies filters to existing photos. It unfortunately doesn't allow you to manipulate the effects in the same way as the Photoshop mobile app, although it does provide you with an infinite(?) number of Plastic Bullet-ified versions of your photo to choose from. Red Giant is known for their professional grade video editing plugins, so I figured I'd take this app for a whirl.
