This app is Inoperable on iPhone 5 running iOS 6.0. While it does load and some of the button produce a response, it is unable to access the camera and does not return any color temperature value.
After reading other reviews, it seems possible that LightSprectrum does function on some iPhone models running older iOS versions.
However, no warning is made in the store description regarding hardware or OS software limitations - so its being misrepresented as a universal app compatible with all hardware and iOS versions.
In addition, the developer Website link provided by the Store is broken.
I have filed a complaint and asked for a refund.
Caveat emptor!
Camerabuff about LightSpectrum Pro