The camera uses terahertz radiation, a kind of radiation that falls between the microwave and infrared spectrums. It has the unique ability to make different chemicals produce their own distinct frequencies. This is what helps it tell the difference between ink and paper, and therefore detect individual letters and words on a page.

Another cool feature of terahertz radiation: its ability to come out in very short bursts. Just as smaller pixels help improve the resolution of an image, shorter radiation bursts improve the resolution of a scientist's data. This level of resolution helps the camera's built-in sensor know when it has passed through an individual page.

As of 2016, the camera was only strong enough to read through the first nine pages of a book, but the researchers are confident that technological improvements will come soon. Once the camera is ready for prime time, it will prove useful for museums, libraries, and other facilities that need to examine historical documents that could be damaged with the slightest touch.