Unlock This Mystery|
Posting Number 2780 Date: 08/23/17 Return to Posting List
Alan, Enjoyed the black glass edition. A glassblower once told me that a true black glass could not be achieved. This was a while ago and I think the reason had to do with the opaque nature of glass itself. I have looked at many black types - satin, etc. They all show the purple-red at some point.
I believe that there is a club member that has experience in glass chemistry who might unlock this mystery. Thanks. Regards, Jeremy Hayes
Some Unlocking of the Mystery of Black Glass
Michael Krumme is a major collector of black glass. Without regard to Steuben he shares this outline when giving a talk on black glass.
BLACK versus BLACK AMETHYST Glass by Michael Krumme
Much is made over the difference between "black" glass versus "black amethyst" glass or even "black milk glass." All you have to do is go to a flea market or a show and pick up a piece of black glass to examine it, and nine times out of ten the seller will descend upon you and proudly state something like this: "That's an old, old, piece of black amethyst glass. It's not black, it's the good stuff. Now, you know how to tell the difference between that and plain-old black glass, don't you?" Then they regale you with the old "hold it up to the sun or other strong light" spiel and show you the color that comes through, which is usually an amethyst hue.
As a collector of black glass, what bothers me about this scenario is that people take an interesting but incidental attribute or characteristic about this glass and turn it into a litmus tet to pronounce a piece as high or low quality. Whether a piece shows amethyst (or any other hue) when held to light is irrelevant to the QUALITY of the piece in question. The lowest quality machine-blown vase may show a lovely amethyst hue when held to light, while a pressed piece of graceful streamline moderne design may not allow any light to pass through due to its thickness, and thus show no color at all. If certain collectors prefer one over the other, that is a matter of taste. I do object to the application of bogus criteria to judge a piece's quality. It is a standard based on ignorance, rather than an understanding of how the glass was made and why its characteristics vary.
Quite simply, manufacturers of black glass intended for it to appear black to the naked eye, under normal lighting conditions. This is not to say that they were unaware that the glass might show other hues in strong light; only that it was not a 'selling point." The strongest evidence for this is the near-total dearth of any original company printed materials which call this color anything other than 'black" or "ebony." Only once do I recall having seen a reprint of an original glass company ad which called their black color "black amethyst." Hence, my feeling is, if the glass companies made no distinction, why should we? Why not judge the ware on its other attributes, e.g., quality of the metal, shape, finish, etc?
As for the manufacturing aspect of black glass, its primary coloring agent was manganese which was also an ingredient in formulae for purple glass. Ah, a connection! Let me quote a lengthy paragraph from "A Collector's Guide to Black Glass" by Marlena Toohey (Copyright 1988, Antique Publications, Marietta, Ohio.) I think this puts the last nail in the coffin of the "black amethyst is better than black" myth:
"Manganese, however, was merely a convenient ingredient of which to add enough to darken the glass to black. The purple or other color, not being visible in normal use, was of little or no concern to the manufacturer. Harry Bastow, a practical glassmaker, explained in 1908: 'Black is commonly produced using an excess of colorants ... The small amount of light that us transmitted through this glass is usually purple, blue, etc., according to which colorant is in the greatest excess, but this is rarely of sufficient importance to require careful balance ... as a matter of fact, black glass is commonly used as a dumping ground for using up cullet of any and all colors."' [emphasis mine.]
In short, if manufacturers considered black glass that showed certain hues in strong light better than wares that did not, why did they then not bring out this aspect in their sales literature? My answer is, of course, they didn't make that distinction because it was a false distinction, a myth that probably arose in later years when this glass began to hit the flea markets. In the pre-politically correct era, we would have called this an "old wives' tare." Holding black glass up to strong light is, in my mind, a kindergarten trick, and a "test" that reveals very little. Like any kind of popular myth, though, it seems to have a life of its own, and even the facts cannot persuade yokels and poorly-read dealers to stop using this as a criteria. If you want to be treated like an idiot, try to explain this to such folk.
That having been said, people seem to value the "amethyst-showing" wares more highly. I have over 200 pieces of black glass, and some of the rarest, most beautiful items I own show no transparency when held to light.
For a sampling of some beautiful pieces of black glass from my collection, you may wish to purchase a videotape of a program I presented to the Southern California Collectors Conference on "Black Glass of the 20s and 30s" in June 1997. Contact David Lisot of Media Resource Corporation, (310) 553-0509.
* Cullet is a glassmaker's term for broken pieces of glass which are added to help make the batch of glass melt faster. Typically, glassmakers would use only cullet of the same color when adding it to a batch.
c. 1997 Michael Krumme, all rights reserved.
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