Tuesday, January 11, 2011

Michael Krumme of Los Angeles adds some information on black glass.

I recall that Marlena Toohey, author of the Collector’s Encyclopedia of Black Glass, states (or rather, quotes from an industry source) that when glassmakers made a batch of black glass, they would often use it as a “dumping ground” for accumulated glass cullet of various colors, adding enough manganese to the batch to ensure that the color came out black.

That being said, I strongly suspect that the quality level of Steuben and Sinclaire glassware is such that their glassmakers would not do this. Obviously there was a more sophisticated level of awareness of glassmaking chemistry at these art glass companies than there was at glass companies making more utilitarian wares. Simply put, I suspect that using the wrong kind of cullet could throw the batch off. However, perhaps there may have been a selective use of glass cullet of various colors when making a batch of Mirror Black or Nubian Black?

Does anyone wish to comment on the use (or non-use) of cullet in glass batches at Steuben? Perhaps this could account for some of the variations in color that we see in Steuben and Sinclaire wares in black.

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