Android Photography App Double Exposure

I would like to create an android app that would combine two photographs together to create something similar to what you would see in a double exposure photograph. Can you give m

Solution 1:

To get a true double-exposure, all you should need to do is add together the R/G/B values for each pixel with straight addition, with an upper limit of 255 for each component(for 24bpp at least). If it's too bright, you can always reduce it down some afterward.