Foto's

This picture was taken in the Bradbury building. It is one of the oldest buildings of Los Angeles. This building hosted a major scene of the movie “Blade Runners”. The picture is the reflection of my friend Carlos from a very old window when glass window was made from molten glass and poured over a large surface. It gives a characteristic of an uneven surface.

We've made glass in many forms for about 4500 years. But two features of glassmaking are surprising. First, glassmaking processes have been far harder to invent than we imagine. The second surprise is that artisans could make really fine glass tableware long before they could make a good windowpane.

Medieval glassblowers made two kinds of flat glass sheets. One technique was to blow a large cylinder. They then cut the cylinder open and flattened it out while it was still hot. The other flat glass sheet was called crown glass. They made it by spinning molten glass and letting it spread from a central point. Crown glass was the most common flat glass for a long time. It underwent considerable refinement. But, even as late as 1800, most domestic windows still displayed a characteristic umbilical imperfection called a crown at their centers.

The French developed the superior plate glass process in the latter 18th century. First a glass plate is poured out in a mold. Then the glass needs expensive grinding and polishing.

To provide common people -- you and me -- with good domestic windowpanes required a continuous mechanized process. Molten glass had to be rolled out in smooth continuous sheets. That couldn't be done until we had modern process machinery. It was in the early 1800s that the first inexpensive rolled window glass became available. That was little over a century and a half ago.