The Collaborative International Dictionary of English v.0.48:

Photology \Pho*tol"o*gy\, n. [Photo- + -logy: cf. F.
   photologie.]
   1. The doctrine or science of light, explaining its nature
      and phenomena; optics. [Obsolescent]
      [1913 Webster]

   2. The science of photography.
      [PJC]