I’m spent two years messing about with theatre lights at my high school and I’ve been wondering something.
What exactly to the three-letter ANSI codes for quartz lamps mean? I mean, the first letter seems to be so that the lamps can be grouped by instrument type (E for Ellipsoidals, B for Fresnels and D for giant lamps for old lights we don’t even have anymore.
I figured somebody here might know what it all means.
According to ANSI, they are assigned arbitrarily. The sole purpose being that any bulb with the correct code will work for that socket. I do agree that they seem to fit into groups based on the first letter, but there are exceptions. It could be that they assigned them sequentially and the bulbs happened to be semi-grouped in whatever documents they used to make their own list. Then again, maybe they do mean something and they’re just not sharing.
Some of the newer bulbs have numerical designators now, just making life that much more fun.