Architectural glass percent of the world's flat glass is produced by the float glass process invented in the 1950s by Sir Alastair Pilkington of Pilkington Glass, in which molten glass is poured onto one end of a molten tin bath. The glass floats on the tin, and levels out as it spreads along the bath, giving a smooth face to both sides. The glass cools and slowly solidifies as it travels over the molten tin and leaves the tin bath in a continuous ribbon. The glass is then annealed by cooling in an oven called a lehr. The finished product has near-perfect
Architectural glass which it is carried by a system of rollers. The polished plate glass process starts with sheet or rolled plate glass. This glass is dimensionally inaccurate and often created visual distortions. These rough panes were ground flat and then polished clear. This was a fairly expensive process. Before the float process, mirrors were plate glass as sheet glass had visual distortions that were akin to those seen in amusement park or funfair mirrors. The elaborate patterns found on figured (or 'Cathedral') rolled-plate glass are produced in a similar fashion to the rolled plate glass process except that the plate is