Tuesday, January 11, 2011

From Rande Bly, his summary on what makes black.

Apparently the story of Sinclaire just adding cobalt to his cobalt blue to make black was not just that simple.

I have taken the results so far and made a column each for Steuben and Sinclaire. It sounds like so far it is possible they are two colors of black. The Sinclaire was reported by Charley Giard to be the color of the potassium permanganate. Michael Krumme used the term amethyst to describe the Sinclaire. Charley Giard, Ed Moland, and Ed Kniss report a red in Steuben. Both Ed’s report a cobalt in Steuben.

The last black Steuben I looked at was an Ivory Goblet with black foot. What I did see was a variation in the color. I saw a spot where the dot of the sun was red. I saw a small portion which looked to be like a small cobalt patch that was not stirred completely. The rest was kind of a cross between the two colors.

Maybe the deciding difference would be the red. There is also the possibility that the Sinclaire black is more homogeneous and will display a single color of Amethyst while the Steuben will display a little more variety of color. Steuben’s black might also be more dense in color and may block the color of the sun in relation to thickness faster than Sinclaire’s. If Steuben continues to show red and Sinclaire shows amethyst or potassium permanganate we may have something here.

Some pieces probably will be too thick to test like this but maybe it will work on 75% of them?

Always try to find the thinnest part of the glass. This may be found near the edge of a foot, in the widest part of the body, or right to the tip of a rim. Check it in more than one place if you can for any signs of variation within the glass.

It would be nice if the red continued to show up in Steuben and was absent in Sinclaire. I would like to thank everyone for their help.

Rande Bly

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