For centuries, lead came was the only material to join pieces of stained glass. The lead not only served as a support, but also formed part of the design of the stained glass piece.
The Lead came technique is the traditional method that was developed as the art form became prominent in 12th and 13th century European cathedrals. This method involves holding pieces of glass together in a network of lead H-shaped channels. The channels are then soldered together where they intersect, and the window is cemented (or grouted) to clean and seal the glass into the lead. Technological advances and experimentation carried out in the field of architecture throughout the 20th century have introduced new materials for this support. The properties of these materials have increased lightness to stained glass and have allowed development of designs that are more daring and avant-garde.
Copper foil was the first structural material that broke with the traditional technique of using lead came between panels of stained glass. The main difference between copper foil and lead came is that it is a much lighter material and allows more flexibility in construction and design. Louis Tiffany used it frequently, especially for lamps used for residential decoration.
The copper foil technique was developed in the late 1800s by Louis Comfort Tiffany (thus, windows made with this technique are often referred to as "Tiffany style" even though they often bear little or no resemblance to actual Tiffany Studios work). This method involves wrapping the edge of each piece of glass with a copper foil tape. The pieces are then laid in place and the foil tape is soldered to hold the pieces together. This creates a connection that is strong, versatile and lighter than lead came. The panel is then cleaned and a chemical patina can be applied to the solder seams to darken them. Copper foil is much stronger than lead when soldered, needs no putty, is waterproof, and allows intricately detailed projects to be constructed where the bulky look and weight of lead would detract from the aesthetics of a delicate design.
Since the solder is applied by hand, the artist can vary the appearance of the line to complement the design of the stained glass piece.
