Monday, 6 August 2012


Flashbulbs were a revolution when they were first invented. They improvised on the other flash systems by actually containing the explosion inside of a glass chamber which could otherwise throw burning embers over the subject and emit large quantities of smoke. The flashbulb is a glass envelope containing fine metal wire or foil (commonly magnesium or zirconium) that is made to burn in an oxygen-rich atmosphere. The bulb has a lacquer on it that prevents the glass envelope shattering when the contents burn – this may be coloured blue to balance the output of the bulb to daylight colour temperature.


Flashbulbs were produced in all kinds of shapes and sizes in varying power. There were special flashbulbs designed to fit very special situations to be used with slow shutter speeds on leaf shutter cameras and to be used with high speed sync in cameras with focal plane shutters. Some burnt instantly while some were slow burners, putting out consistent light over a time of say 1/30 th of a second. Depending on the speed of burn of the bulb different camera manufacturers even provided different synchronization options (refer article Types of Flash Sync).

Types of Flashbulbs

F – Fast bulbs were bulbs which took approx 5ms to peak and had duration of less than 10ms (at half peak). Fast bulbs could be used with the X sync mode of cameras employing leaf shutters at up to 1/100 of a second.

X – X stands for bulbs that lay between the F and M category. They take 10-18 ms to peak and had a flash duration of 8-10ms.

M – Medium fast bulbs had a timing of 18-20ms to peak and a flash duration of 8-12 ms

S – Slow bulbs which took approximately 30ms to peak and had a long flash duration of 20-30ms. Due to its long flash duration, S type bulbs could be used with leaf shutters at speeds not higher than 1/20 s, but had guide number significantly higher than other flashbulb types.

The major disadvantages of flashbulbs were that they were one time use only and needed to be replaced before the photographer could shoot again. The bulbs after use will stay hot for some time making the job all the more difficult. Many systems came into being to solve this issue, Flash cubes, Magicubes (X flash cubes), Flipflash, Philips Top Flash, Polaroid Flash Bar, and the Sylvania Flip Flash just to name a few. They made rapidly changing flash bulbs possible with flash cartridges of various designs holding multiple flash bulbs and which would automatically switch bulbs between shots. But they were all no match for the electronic flash units of modern times. With the advent of modern day electronic flash all but the very specialist categories of flashbulbs were put out of use.

A Used Flashbulb
A Used Flashbulb

Although flashbulbs could not match the convenience and functionality of electronic flashes there still exists a specialist market for flashbulbs, especially the larger flashbulbs with high output. No other portable light source could match the intensity of light of a large flash bulb and the best thing is that they require no electricity and could be easily triggered by a portable battery making them a favourite accessory of Cavers worldwide. Thus the flashbulb now finds use in lighting grand subjects especially when they are situated at hard to reach corners of the earth.

Flashbulbs are also used whenever a situation demands very high intensity of light. Flashbulbs also offer the photographer a flexibility to choose different flash durations. They are available in many varieties a slow burning bulb with a flash duration of 20 – 30 ms could be used with the high speed sync function and flood flash bulbs which produce enough light to make exposures of 1/40000th second possible with special cameras.

In the next article we will discuss about Photography - Lighting - Flash - Flash Guide Number

Related Reading

  1. Flash
  2. Continuous Light
  3. Fluorescent Light
  4. Gig Photography
  5. Neon Light