a considerable portion of the beam of light 22 passes through the cell as indicated by the arrows 23 fig5 shows a light valve 27 that includes a film 24 comprising a cross linked polymeric matrix material in the form of a transparent plastic 25 in which a plurality of dark droplets of liquid light valve suspension 26 containing the carbon flakes 21 is distributed the globules are dark because the carbon flakes 21 within them are strongly light absorbing the light valve 27 has a protective layer 29 and an electrode 28 placed on both sides of the film 24 in this embodiment the electrodes 28 are on the inner surfaces of the protective layers 29 and in contact with the film 24 dielectric overcoatings not shown may also be placed over the electrodes if desired the protective layers 29 and electrodes 28 in this embodiment are permanently secured to the film 24 fig6 illustrates another embodiment of the light valve 27 in which protective layers 29 which have an electrode 28 on one side of each protective layer are again placed on both sides of the film 24 however unlike the embodiment shown in fig5 in this embodiment the electrodes are on the outer surfaces of the protective layers 29 and are not in contact with the film 24 again the protective layers and electrodes in this embodiment are permanently secured.