Flashbulb technology did not evolve as much as film technology. As film emulsions evolved to become more sensitive (“faster”), it reduced the amount of light required to properly expose the film. Color film brought about another wrinkle in flash bulb type – to properly expose color film the outside of flashbulbs are coated with a blue pigment. After the flash number, an added “B” designation follows to identify bulbs that have blue pigmentation for use with color film. As electronic flash technology evolved in efficiency, size, and price it replaced flash bulbs during the 1970’s.
Earlier examples of flashbulbs (1930’s – early 1950’s) are near the size and shape of a standard light bulb. They put out a LOT of light. One of the largest production bulbs was the G.E. #50, which produced around 70,000 lumen-seconds of light. The “miniature” flash bulbs that became standard kit for press photographers from the early to mid-1950’s are egg-sized bayonet mount flashbulbs. They were produced by Sylvania as the Press 25 and by General Electric as the #5. The two different brands can be considered interchangeable. Remember the blue designation – boxes of bulbs could be purchased as “25” or “25B” as well as “5” and “5B”.
Large (Light Bulb-Sized) Flash Bulbs
The “miniature” flash bulbs that became standard kit for press photographers from the early to mid-1950’s are egg-sized bayonet mount flashbulbs. They were produced by Sylvania as the Press 25 and by General Electric as the #5. The two different brands can be considered interchangeable. Remember the blue designation – boxes of bulbs could be purchased as “25” or “25B” as well as “5” and “5B”.
Press Bulbs
As film formats became smaller and more sensitive to light, the flash bulbs became smaller as well. While the literature of the 1950’s discussed the press-sized bulbs as miniature, the smaller bulbs had a friction fit style and were designated as “M” bulbs. The M2, M3, M5, M25 had the similar new smaller standard fitting.
M bulbs
The smallest, and newest sized standard flash bulb is called the “peanut” size due to the size and shape of these bulbs. They were designated “AG” bulbs and had a number after them to show brightness and the “B” designation if they were coated blue for color film.
AG Bulbs
The AG bulbs can be single bulbs, or placed inside 4 bulb flash cubes that rotated, or on a panel of eight bulbs that plugged into a 110 film instamatic. The Flip Flash would flash through a sequence of four bulbs, then the photographer would flip the panel over to expose the final four….
These exciting innovations heralded the beginning of the end of flash bulbs in the 1970’s. Electronic flashes quickly became an affordable alternative to flash bulbs.