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A Short History of Electric Lightby Frank Andrews |
For comparison, an 1860 Oil lamp with a single flame produces approximately 2,500 lumens, see also press reports after tables.
| Incandescent Lighting | ||
|---|---|---|
| (An approximate lumen output is given for a Standard size bulb) | ||
| Edison’s first bulb | 1.4 lumens per watt. | |
| Best carbon filament.16 cp. bulb = approx. 50 lumens | 3 to 4 lumens per watt. | |
| Cruto’s synthetic carbon | 4 lumens per watt. | |
| Cruto’s deposited graphite | 3 lumens per watt. | |
| 1905 | Metallised carbon filament. Annealed carbon by Willis Whitney. |
4 to 5 lumens per watt. |
| 1897-1912 | Nernst lamp | 6 lumens per watt. |
| 1907 | Squirted Tungsten 30 cp. bulb = 240 lumens |
8 lumens per watt. |
| 1910 | Drawn Tungsten 32 Watt bulb = 320 lumens |
10 lumens per watt. |
| 1912 | ‘Half-Watt’ (Coiled filament) 40 Watt bulb = 480 lumens |
12 lumens per watt. |
| 1933 | Coiled-coil, 10-15% better than coiled filament. 60 Watt bulb = 800 lumens |
13 to 14 lumes per watt |
| 1959 | Tungsten-halogen 40 Watt bulb = 800 lumens |
20 lumens per watt. |
| 1986 | Modern bulb (standard) 60 Watt bulb = 960 lumens |
16 lumens per watt. |
| After 86 | ??? | to be determined 2003 |
| Non-Incandescent Lighting | ||
|---|---|---|
| 1898 | Moore Tubes | c. 8 lumens per watt. |
| 1931 | Low pressure sodium discharge | 50 lumens per watt. |
| 1938 | Fluorescent (Calcium Tungstate) | 30 lumens per watt. |
| 1946 | Fluorescent (Halophosphate) | 60 lumens per watt. |
| 1973 | Three band | 90 lumens per watt. |
| 1986 | Low pressure sodium discharge | 200 lumens per watt. |
Press reports in 1907 gave very detailed accounts of the cost savings of tungsten lamps:
Comparative cost per 1,000 hours of use.
Gas with incandescent burner consuming 4 cubic feet of gas would have cost 18s with gas at 3s per 1000 cubic feet.
An Osram tungsten lamp of 32 cp. and consuming 35 watts per hour would have cost 11s 8d with electricity at 4d per unit.
A Carbon filament lamp of 32 cp. and consuming 105 watts per hour would have cost 35s with electricity at 4d per unit.
A Tantalum filament lamp of 22 cp. and consuming 40 watts per hour would have cost 13s 4d with electricity at 4d per unit.
It is noted that with this cheaper light that ‘the poorer classes need no longer have there small, and often badly ventilated rooms, further vitiated by gas burners or oil lamps, since the new lamp brings the luxury of electric light within the reach of all.’
Mentions the competition between gas and electricity, each stimulating the other. Incandescent lighting having led Auer von Welsbach to develop the incandescent gas mantle. The irony of Auer having then gone on to produce the first metal filament, osmium, lamp which was to lead to the demise of gas for lighting, did not go unnoticed by the reporter. It refers to tungsten bulbs as having twice the life expectancy of carbon bulbs and compares light outputs, one tungsten bulb being better than two carbon and still costing less to run.
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