Yesterday Cramden posted pictures of some nice Christmas light original shades. He and I then had a brief back and forth about the lights. For the one or two of the readers who did not follow the Christmas Light discussion and actually care I thought I would provide background and a few pictures.
Today most Christmas lights are LED’s and most people seem to decorate with the small miniature size. However some of us are stuck in the past and prefer the larger incandescent bulbs. We referred to two types in our posts, C9 outdoors and C7 indoors.
Way back when Christmas lights were new manufacturers adopted a nomenclature for them. “C” meant cone shaped and the number was the diameter at the widest point in 1/8ths of an inch. Most common were C6, C7 and C9 but these were usually called C6 1/2, C7 1/2 and C9 1/2, the actual diameters of the glass at the widest point (C7 would be 7/8”). Other designators were “G” for globe and “D” for decorative.
This system got to be too complicated for the consumer and did not speak to the socket size. In 1972 the manufacturers changed the system. “C” now meant Christmas and the number defined the socket size. “6” is miniature, “7” is candelabra and “9” is intermediate. A standard bulb socket is “medium.” So if a Christmas light package has a size with a “1/2” in it the package was made prior to 1972.
Some pictures. The first picture shows a modern C7 bulb on the bottom and a late 1950’s production C7 1/2 on the top. Looking closely the shape of the glass has changed, the old bulb on the top has straight angled sides, the new one on the bottom has bowed sides. The wattage has also been reduced for cooler operation.
The second picture is an OB of GE C9 1/2 bulbs from about 1940. Prior to WW2 GE used Mazda (God of light) as the branding for their high end bulbs. After Pearl Harbor GE immediately dropped the Mazda name. The third picture is one of the C9 1/2 bulbs inside the box. It is flame swirl molded glass with inside frosting rather than outside painted. These are the bulbs I use on the exterior of the house, it takes some work to keep finding working replacements.