Finite temperature field theory with boundaries: The photon field

We calculate the deviations from Planckian form of the photon field finite temperature stress tensor in a manifold with boundary, due to scattering from the boundary. Familiar non-intergrable divergences are found in the photon stress tensor as the boundary is approached and these are shown to be an inescapable consequence of initial calculational assumptions. Modifications of these assumptions are discussed which serve to remove the divergences and to illustrate the importance of the role played by surface gravitational actions