Photoflood lamps are a type of incandescent light bulb designed for use as a continuous light source for photographic purposes.[1] The filaments of such lamps are operated at much higher temperatures than is the case for standard, general lighting service lamps. The result is a brilliance of light much higher than the lamp's wattage rating would suggest. The trade-off is that the lamp has a very short service life of seldom more than ten hours.
Photoflood lamps were used by photographers and film makers as a continuous lighting source. However for photographers, such use has been overtaken by the use of high power studio flash units many of which also provide a lower power light for modelling purposes.[2] Film makers have turned to longer lasting tungsten halogen lamps which, in their turn, are being overtaken by light-emitting diode (LED) lamps.[3]
Photoflood lamps are still used in special cases by the motion picture industry. Where an illuminated lamp is required on set as part of the dressing, the light fall from a normal light bulb would not be visible on film as it would be swamped by the bright studio lighting. The ordinary lamp is replaced by a photoflood bulb whose intense light is easily visible on film (and if so required, is bright enough that it can form the sole illumination for the shot).[4]
Photoflood bulbs are available in a number of sizes. The two most common sizes have these characteristics.[5]
| 100 watt lamp | 100 | 1630 | 16.3 | 750[6] | |||
| No. 1 photoflood | 250 | 6500 | 26 | 3200 | 20[7] | ECA | |
| No. 2 photoflood | 500 | 17,800 | 35.6 | 3400 | 6[8] | EBV |
| 100 watt lamp | 100 | 1200 | 12 | 2900 | 1000[9] | |
| No. 1 photoflood | 275 | 8500 | 30 | 3400 | 3[10] | |
| No. 2 photoflood | 500 | 14,400 | 28.8 | 3400 | 6[11] |
Note that in each case an ordinary 100 watt lamp is provided for comparison purposes.