The Blues
At least 16 different blues have been attributed to various items of Carder Steuben. Many of these blues have long since been forgotten, making the task of identification monumental. Some hues, on the other hand, were so popular that they survive today and are commonly known and appreciated by all. Most notable of the easily recognized blues is celeste blue.
There are several methods for identifying color shades. The best and most accurate, albeit simple, is the examination of old Steuben advertisement photographs. Persian blue is one hue that can be identified by advertisement. Persian is so similar to celeste that it is often mistaken for celeste.
Another method of color identification is the black light method. Using a black light in an otherwise pitch black room reveals the presence or absence of uranium in the glass formula, thereby helping in the identification process. Glass formulas containing uranium fluoresce. Not all Carder Steuben glass formulas contained uranium, and therefore not all Carder Steuben glass responds to black light. The intensity of the fluorescence indicates the amount of uranium in the glass.
A third method of hue identification requires researching the Carder Steuben's original blueprints. Only certain items were available in certain hues. Therefore, identification can often be accomplished by process of elimination. Rose blue is often only identified by this third method as it, like Persian, appears very similar to celeste blue.
