Units of paper quantity was ordered by the ream of 480 sheets. In 1840, a ream in Lisbon was 17 quires and 3 sheets = 428 sheets, and a double ream was 18 quires and 2 sheets = 434 sheets; and in Bremen, blotting or packing paper was sold in reams of 300 (20 quires of 15 sheets). A mid-19th century Milanese-Italian dictionary has an example for a "risma" (ream) as being either 450 or 480 sheets. In the UK in 1914, paper was sold using the following reams: Reams of 500 sheets were mostly used only for newsprint. Since the late 20th century,
Electronic paper technological advantages. All electronic paper technologies face the following general challenges: Electronic ink can be applied to flexible or rigid materials. For flexible displays, the base requires a thin, flexible material tough enough to withstand considerable wear, such as extremely thin plastic. The method of how the inks are encapsulated and then applied to the substrate is what distinguishes each company from others. These processes are complex and are carefully guarded industry secrets. Nevertheless, making electronic paper is less complex and costly than LCDs. There are many approaches to electronic paper, with many companies developing technology in this area. Other