There are any number of Steuben colors that are listed in various factory records that we do not now know what they look like. Collectors have been known to make up a name for a color if they didn’t know the factory name. Such was the case with “blue-gray”. Recently there has been a great deal of work on Steuben colors being done by Dr. Greg Merkel using X Ray Florescence (see the article below). He has compared the formula generated by X Ray Florescence for a piece of “blue-gray” with formulas for various colors found in Carder’s notebooks. He has found that the formula for “blue-gray” matches the formula for Antique Green.

Steuben’s Wisteria is a dichroic glass. It appears to be a different color depending upon the light. In natural or incandescent lighting it appears to be a light pink or lavender. In florescent lighting it is a light blue. The photo is a 6593 Wisteria candlestick shown in florescent lighting on the left and incandescent lighting on the right.

Steuben would sometimes finish an acid etched piece by essentially painting it with a brown coating. To quote Paul Gardners The Glass of Frederick Carder page 65, A brown oxide, such as burnt umber or ocher mixed with linseed oil and turpentine, was frequently rubbed into the etched surfaces to accent the design. This color was not fired on, but was a fairly permanent air-dried pigment.This technique was used most often with a single light colored glass such as Alabaster, Calcite or was colorless. The glass shown here is shape 6806 in colorless glass etched in an unknown pattern that may be Trentham. The photo shows an original burnt umber finish. Unfortunately collectors today who are not aware that such a finish exists will often assume that the glass is very dirty and go to some effort to remove the finish. Sometimes pieces will be found where the finish removal has not been entirely successful and the finish will still remain in crevices.

Steuben would sometimes finish an acid etched piece by essentially painting it with a brown coating. To quote Paul Gardners The Glass of Frederick Carder page 65, A brown oxide, such as burnt umber or ocher mixed with linseed oil and turpentine, was frequently rubbed into the etched surfaces to accent the design. This color was not fired on, but was a fairly permanent air-dried pigment.This technique was used most often with a single light colored glass such as Alabaster, Calcite or was colorless. The glass shown here is shape 6806 in colorless glass etched in an unknown pattern that may be Trentham. The photo shows an original burnt umber finish. Unfortunately collectors today who are not aware that such a finish exists will often assume that the glass is very dirty and go to some effort to remove the finish. Sometimes pieces will be found where the finish removal has not been entirely successful and the finish will still remain in crevices.

Commercial X-ray florescence instrumentation exists that is capable of non-destructively determining the elemental analysis of various materials including glass. The instrumentation is portable, will detect elements between aluminum (atomic number 13) and uranium (atomic number 92) inclusive and, if properly calibrated, will determine the percentage of each element in the material. An effort is presently under way to provide a more definitive correspondence between the factory color names and the colored glassware itself through non-destructive chemical analysis of Carder Steuben objects and an interpretation of their chemistry in light of information within Frederick Carder’s laboratory notebooks. The results of this study form the basis of an upcoming book on the identification of Steuben colored glassware and the chemistry behind its appearance.

Some recent work (August 2011) using X-ray florescence to analyze two Steuben glass pieces has resulted in defining two colors that were not generally well known. One of these colors is Canterbury and the other is Celadon. Shown here is a 2956 candlestick in Canterbury. A champagne in Celadon is shown below.

This 6692 champagne has been analyzed by X-ray florescence. The analysis shows that the color of this piece is Celadon. This color has earlier been called Window Glass Green and Nile Green but it is, in fact, Celadon. Celadon contains Uranium so exhibits florescence in visible light.