Driving methods for variable transmission electro-phoretic media

A method of driving a variable transmission film comprising a layer of electrophoretic material disposed between two light-transmissive electrodes, the electrophoretic material comprising a fluid containing a plurality of charged particles capable of moving through the fluid upon application of an electric field between the two light-transmissive electrodes, the method comprising:

• applying a first voltage waveform having a frequency from 1 to 10 Hz to the film having an initial optical state;
• and
• applying a second voltage waveform having a lower frequency and shorter pulse duration than the first voltage waveform to switch the film to a final optical state, the frequency of the second voltage waveform being 1 Hz or greater,
• wherein the variable transmission film has a higher percent transmission at the initial optical state than the final optical state, when viewed through the variable transmission film.