Ive been looking for an app like this! Only wish it would work as an overlay with EVERYTHING I have on my iPad. There is nothing worse than turning on the iPad in the middle of the night & being blinded by the intense white light. Health wise - a white light disrupts the Circadian rhythm of the body which leads to all sorts of health issues. This app is a great start and I hope the developer will build on it & expand its application.
RenaCanada about Red Shift - Night Browser and Maps, v1.0