scotograph

noun3

1. •
   An image of a ghost or other apparition appearing on unexposed film.

   • The spirit-faces are sometimes obtained on ordinary paper without the aid of a camera and are called Scotographs. — 1946
2. •
   (no longer used, rare) An impression made on a photographic plate by a radioactive substance without the intervention of any opaque object other than the screen of the plate.
3. •
   (no longer used, rare) An instrument for writing in the dark, or by the blind.