rolled plate glass, discontinuous
The Romans already produced their window glass in more or less this manner. They poured molten glass mass onto a flat surface, and then straightened it out.
The “modern” process does not differ widely. Molten glass is poured onto a metal plate and flattened with rollers.
Afterwards, the glass needs to cool down slowly. Then it is ground and polished until the last irregularities have disappeared, and the glass is entirely clear – a complex and time consuming procedure.
Rolled plate glass can be produced in fairly large dimensions. Hence it was used primarily for large panes such as shop windows and large mirrors.