With so many apps that apply filters to your photos it's getting harder to find the good ones. Add RebelSauce to the list of clever photo editing apps for iOS. This US$0.99 app has almost infinite variations that mimic classic film styles. Of course there are the usual editing tolls like crop, brightness, saturation and color temperature, but the app gets interesting in the application of grain, old film styles, and different tonalities to your photos. Each filter that you apply has a + and - button, so there is a lot of control. If you are willing to experiment, the variations are incredibly wide.
As much as I liked the filters, I thought the app was rather opaque in operation. When you first open it, there are on-screen guides, but it wasn't always obvious what those guides were trying to reveal. When you actually start using the app it can be confusing too. Back and forward arrows make changes, but not always the expected changes. A forward arrow might mean save your work, but instead it takes you to output options or destinations. A left arrow means your edits will be lost, with a warning, happily, to prevent disaster. After awhile I figured it out, but it could have been a lot more intuitive.
RebelSauce is still an excellent filter package. The filters never go overboard, and there is enough flexibility to get exactly the look you want. I especially liked the variable application of film grain.
RebelSauce has a variety of $0.99 upgrades for different kinds of filters, and I think the amount of extra purchases is excessive for a $0.99 app. There are 9 purchases, or for $5.99 you can have all 9. Since it is hard to see what each package does in advance, I think the filters are worth avoiding.
RebelSaunce requires iOS 8 or later. It is not universal, and it's optimized for the iPhone 5 and 6 series of phones.