Electrofluidic devices, visual displays formed from the electrofluidic devices, and methods for making and operating such electrofluidic devices Each electrofluidic device has a fluid vessel with first and second regions that contain an electrically conductive polar fluid and a non-polar fluid The polar and/or the non-polar fluids are externally visible external through a viewable area of the second region A voltage source is electrically connected to a capacitor having a hydrophobic surface that contacts the polar fluid and provides a first principal radius of curvature of the polar fluid that is convex and smaller than a second principal radius of curvature of the polar fluid in the first region The voltage source applies an electromechanical force to the polar fluid, thereby transferring the polar fluid from the first region to the second region and causing a spectral property of light transferred through the viewable area to change.