An electro-optic display (102), or a sub-assembly of such a display, comprising a layer of electro-optic material (108) on a backplane (100) is assembled using at least one release sheet (112, 116) or masking film having a resistivity not greater than about 10.sup.13 .OMEGA. square. The use of such a release sheet or masking film helps to avoid damage to transistors in the backplane during the assembly process.