US 2326004 A
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oearcn KOOITI Aug. 3, 1943. BARRETT 2,326,004
LAMP FITTING FOR USE IN FLASH-LIGHT PHOTOGRAPHY Filed April 28, 1942 INVVENTOAI flrl'hu r Barre Z1 WPEQS ATTORNEY Patented Aug. 3, 1943 searcn m LAMP FITTING FOR USE IN FLASHLIGHT PHOTOGRAPHY Arthur Barrett, London, England Application April 28, 1942, Serial No. 440,794 In Great Britain November 18, 1940 1 Claim.
The present invention relates to flashlight photography and more particularly to a fitting for flash-bulbs used in flashlight phtotography embodying the use of spectroscopic separation filters applicable to colour photography.
Heretofore when it has been desired to obtain photographs by infra-red plates or films, with a flash-bulb the bulb has had to be coated with a gelatine filter coating of fairly accurate weight and absorption characteristics.
An object of the present invention is to provide a fitting which enables ordinary flash-bulbs to be adapted for taking infra-red photographs Without the necessity of the delicate operation of coating the flash-bulb. A further object of the invention is to provide a fitting which will enable flash-bulbs to be employed for taking photographs in the black-out without contravening regulations. According to the present invention a fitting for use with a flash-bulb in flashlight photography comprises a casing adapted to fit over the flash-bulb to limit the radiation from the flash bulb to the desired wave lengths.
Preferably the casing comprises a pouch which need not be made wholly of the material employed for filtering the radiation from the flash bulb and may be formed of some opaque material for example leather or other suitably tough flexible material and provided with a panel of the filtering material. This material may conveniently be of Cellophane (registered trademark) or other film or foil suitably dyed to the required colour.
In one embodiment of the invention a pouch is provided with two panels of filter material one on each side of the pouch with a dividing partition inside the pouch of opaque material. One panel is composed of film or toll dyed to a dark red for use in taking infra-red photographs and the other panel is composed of film or foil dyed to a deep violet. The red panel is employed for obtaining infra-red photographs, the central opaque partition being used to prevent any emission through the violet panel, and the violet panel may be used for obtaining exposures with ordinary panchromatic plates in the black-out without contravening the black-out regulations.
Preferably, the pouch is employed with the long-flash type of flash bulb and with fast plates to obtain the best results.
The bottom of the pouch is provided with a cord, Zipp fastener (registered trade-mark) or with press-studs to enable the open end of the pouch to be closed around the flash-bulb to exclude all white-light leak.
An embodiment of the invention is shown in the accompanying drawing in which Figure 1 shows a perspective view partly broken of a dual purpose pouch being fitted over a flash bulb,
Figure 2 shows a section of the pouch as on the line IIII of Figure 1, and
Figure 3 shows the pouch fitted onto the flash-bulb.
The dual purpose pouch shown in the drawing can be used for taking infra-red photographs or ordinary panchromatic photographs and comprises two panels I and 2, each made of several layers of dyed Cellophane (registered trademark) or other film or foil, one panel being dyed a dark red and the other panel being dyed a deep violet. These two panels are sewn together round three of their edges by a leather binding 3, the remaining edge being reinforced and provided with a cord 4, which is threaded through suitably placed holes.
Inside the pouch so formed and held in position by the binding 3, is a partition 5, composed of opaque material, for example, rubberised cloth which may conveniently be silvered.
In use the flash bulb 6 is inserted in the pouch on the side of the partition 5 according to which panel is to be used, and the pouch snugly fitted round the base of the flash-bulb 6, by means of the cord 4.
The deep violet panel may, with advantage, be used when taking ordinary photographs, that is, panchromatic photographs in daylight, since the flash is so dim as completely to eliminate the objectionable dazzle which necessarily accompanies the use of ordinary flash-bulbs, the subject being normally unaware of the flash if used under the ordinary conditions of artificial lighting or daylight so subdued as to call for the assistance of flashlight.
For the ordinary type of flash-bulb the pouch need only be some 5 square and being flat and flexible adds nothing to the bulk or weight of the'photographers equipment and enables only standard bulbs to be carried either for ordinary daylight use with panchromatic or other material or for strictly dark flash work with infrared material or for semi-dark flash work using panchromatic material.
By providing a binding round the edges of the pouch a possibility of cracking along these edges is eliminated and the pouch may be used for a considerable time if reasonable care is taken.
What I claim is:
A casing for a flash-bulb adapted to fit over thereat and said panels having means provided along their fourth edges for fitting tightly around the neck'of the flash-bulb, and a central flexible partition made of opaque material 10- 5 cated between the two panels.