As a GM do you go too easy or too hard on your players when it comes to light? Some games masters often have their caverns and dungeons filled with luminescent fungi or crystals so the characters can continue with an impromptu adventure without being thwarted by a lack of torch light. In other games GMs pay careful attention to the inventory of candles just for that dramatic moment when the brave warriors are cast into darkness.

Light’s important. The ability to see in poor light or darkness is sometimes a racial perk. Forgetting to pay attention to illumination levels in those games is to do players with such characters a disservice.

Light can therefore be quite a challenge? Just how rare are good candles? How much do they cost? Would it be more cost effective to carry a lamp and oil? This post is inspired by some research by William D. Nordhaus who looked into the history of light and compared that to costs. You can download his paper at ideas.repec.org or scan it below.

Two tables have been reproduced below which might be of particular interest to roleplayers and world builders thinking about light. The first is a brief history of light from open fire to (nearly) modern lights.

1,420,000 BCE Fire used by Australopithecus 500,000 BCE Fire used in caves by Peking man 38,000 – 9,000 BCE Stone fat-burning lamps with wicks used in southern Europe 3,000 BCE Candlesticks recovered from Egypt and Crete 2,000 BCE Babylonian market for lighting fuel (sesame oil) 1292 Paris tax rolls list 72 chandlers (candle makers) Middle Ages Tallow candles in wide use in western Europe 1784 Discovery of Argand oil lamps 1792 William Murdock uses coal-gas illumination in his Cornwall home 1798 William Murdock uses coal-gas illumination in Birmingham offices 1800s Candle technology improved by use of stearic acid, spermaceti, and paraffin wax 1820 Gas street lighting installed in Pall Mall, London 1855 Demonstration of electric-discharge lamp by the Royal Society of London 1860s Demonstration of kerosene lamps 1876 William Wallace’s 500-candlepower arch lights, displayed at the Centennial Exposition in Philadelphia 1879 Swan and Edison invent carbon-filament incandescent lamp 1880s Welsbach gas mantle 1882 Pearl Street station (New York) opens with first electrical service 1920 High-pressure mercury-vapor-discharge and sodium-discharge lamps 1930 Development of mercury-vapor-filled fluorescent tube 1931 Development of sodium-vapor lamp 1980s Marketing of compact fluorescent bulb

In this table Nordhaus goes to cross-compare sources of light with the cost to forma price index. It stretches from Babylonian times up to the last century.

Device Stage of Technology Approximate Date Price (cents per 1,000 lumen-hours) Open fire Wood From earliest time Neolithic lamp Animal or vegetable fat 38,000 – 9,000 BCE Babylonian lamp Sesame oil 1750 BCE Candle Tallow 1800 40.293 Sperm oil 1800 91.575 Tallow 1830 18.315 Sperm oil 1830 42.125 Lamp Whale oil 1815 – 45 29.886 Silliman’s experiment;

Sperm oil 1855 160.256 Silliman’s experiment;

Other oils 1855 59.441 Town gas Early lamp 1827 52.524 Silliman’s experiment 1855 29.777 Early lamp 1875 – 85 5.035 Welsbach mantle 1875 – 95 1.573 Welsbachmantle 1916 0.346 Kerosene lamp Silliman’s experiment 1855 4.036 19th century 1975 – 85 3.479 Coleman lantern 1993 10.323 Electric lamp Edison carbon lamp 1883 9.228 Filament lamp 1900 2.692 Filament lamp 1910 1.384 Filament lamp 1920 0.630 Filament lamp 1930 0.509 Filament lamp 1940 0.323 Filament lamp 1950 0.241 Filament lamp 1960 0.207 Filament lamp 1970 0.175 Filament lamp 1980 0.447 Filament lamp 1990 0.600 Compact fluorescent

bulb 1992 0.124

Interested to dig deeper? The Slideshare embed below contains the full paper.