Modern glass is produced by floating the molten glass on top of a ribbon of molten metal to give a uniform thickness and a distortion-free surface. For about 50 years immediately prior to the invention of this float glass method, glass was produced using a machine to draw the glass from its molten state into sheets. This method resulted in some distortion of the surface. Prior to the turn of the last century, glass was generally mouth blown into cylinders and then flattened into sheets by hand. This process produced glass containing various imperfections both within the glass and on its surface.
"Restoration window glass" is used to describe a style of glass produced to replicate both the machine drawn and mouth blown antique products.
View a comparison chart of the Hollander Restoration Window Glass family: