FOIL. The early bulbs were filled with crumpled magnesium foil. The brightness peaked about 1/30th of a second after the bulb was fired. The bulbs were made in various sizes to cover a wide range of illumination needs. Clear bulbs worked for traditional B&W film. Blue bulbs permitted flash shot to be taken with daylight balanced colour-negative film. And the dark red bulbs were used with infra-red film when unobtrusive flash shots were needed.
WIRE. Later bulbs using a ball of fine magnesium wire reach their peak intensity much sooner - 1/50th to 1/60th second after being fired.
GAS FILLED. These bulbs were designed to have a long even peak intensity suitable for use with focal plane shutters.
Since the first cameras used with flash did not have a built-in means to delay the shutter release until the bulb had time to reach its peak, add on devices were sold. Larry demonstrated a device commonly used with the Speed Graphic and similar press cameras. To take a shot, a button on the battery case of the flash was pressed. A fraction of a second later, a solenoid wired to the flash gun pulled up and triggered the shutter release.
The early and larger bulbs were fitted with a standard Edison screw base - like an ordinary incandescent light bulb. In the 1950s, smaller bayonet based bulbs became popular as camera became smaller and films faster. Near the end of the flash bulb era, base less bulbs the size of a peanut were common as individual bulbs, in flash cubes and in flash bars. Some even had built in batteries or mechanical ignition means.
Larry's talk prompted a discussion of the even earlier flash powder devices with their various ignition means. The danger of fire and injury was mentioned. One member of the audience who used flash powder many years ago described how the ingredients were kept separated in two bottles, to be combined only when the need for the flash light was imminent.
Synchronization was not an issue with the flash powder. The photographer uncapped the lens, his assistant ignited the flash, and the lens was once again capped. When asked how long it took before a second shot could be made, The practitioner said he didn't usually make another exposure. He and his assistant exited promptly before the subjects noticed the dust and debris gently floating down on their clothing and food.
ABOUT THE IMAGES. Click on any image and in a few seconds you will see an enlarged view in a separate window. The images were taken with a Nikon 990 digital camera and modified as required in Photoshop. All images are © 2001 by the Photographic Historical Society of Canada and may be used if the source is mentioned.