Engineering Terminology For Vintage Ray Ban Sunglasses
The purpose of this guide is to familiarize the prospective buyer or seller with the correct terminology used in describing features of vintage Bausch & Lomb Ray Ban sunglasses, with a specific emphasis on hallmarking. The following is a list of terms, each with a brief definition and example.
1. Stamp: A mechanical process in which material is displaced (or pushed aside) to create a character or symbol. In this context, this process applies specifically to malleable materials such as metals or plastics. It does not apply to hard materials like ceramic or glass. If you look on the top cross bar of a pair of vintage Ray Ban sunglasses, you will see "B&L RAY BAN U.S.A." This is an example of a stamp.
In more obsolete terms, "stamping" also referred to a process in which an indentation was formed and an ink colouring applied (or added) at the same time. Examples of this can be seen in the logos on early leather Ray Ban cases from the 1930s to the 1960s.
2. Etch: A chemical or mechanical process in which material is removed in order to create a character or symbol. Etching can be done to a wide variety of materials hard or soft, but it is used primarily on hard materials such as glass. The "B&L" symbol found on vintage Ray Ban lenses is an example of etching. Early glass etching was done by mechanical means in the 1930's, but was updated to a chemical method (using) acid in the 1990s. Chemical etching provides a much sharper and well-defined character than that produced by mechanical means.
3. Print: A chemical or mechanical process in which material is added in order to produce a character or symbol. The "Ray Ban" script logo found on post 1982 sunglass lenses is an example of printing. The printing is further bonded to the lens glass as a byproduct of heating the lens (tempering) in order to strengthen it.
4. Emboss: This is a mechanical process in which material is displaced in order to produce a raised design. Embossing was used on early plastic Ray Ban sunglass cases such as those used for the Balorama or Olympian series.
5. Casting: A mechanical process in which a molten material is poured or injected into a mould, then hardened and removed from the mold. This process can produce a raised character, design or symbol on the material. An example would be the 1930s/40s nose pads, which had a raised B&L design on the interior surface of the pad. In the 1950s/60s the nose pads would have the reverse in the form of a B&L indentation in the nose pad.
6. Forging: A block or piece of metal produced by repeated hammering of a semimolten mass. The hammer forging process both shapes and hardens the metal. Further heating and hammering (or machining) is required to produce the final shape.
Credit to treasure-one