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Re: (TFT) One-Hex Fire - how much light?

From: ErolB1@aol.com

Working over my rules for light sources (both magical and non-) I've come up
with a question: How much light would a one-hex Fire spell (or
equivalent-sized non-magical fire) produce?

My initial w/i/l/d/a/s/s/e/d/ g/u/e/s/s/ estimate is that it should be
somewhere between 10x and 100x as much light as a torch, lantern, or Light spell.
But I thought I'd ask the list: Does anyone have any better estimates?

Long dry, series of numbers to follow. I probably duplicate some of your work here. My estimates on a single hex of fire are at the end.

  David Michael Grouchy II

I'm using LUX at the unit of measure. LUX is the unit which indicates the intensity to which a surface is lit, or the brightness of the light shining on a surface at a given distance. While the sun is very bright, the amount of illuminence it puts on a given square meter of the earth varies. This illuminence is called LUX.

   1 lux = light needed to illuminate 1 square meter to 1 lux

or 1 lux  approx = 1 foot candle / 10

or 1 lux  approx = 1 meter candle

(natural values)                  LUX
Direct sunlight             100,000 - 130,000
Full daylight,
 indirect sunlight          10,000 - 20,000
Overcast day                  1,000
Very dark day                   100
Twilight                         10
Deep twilight                     1
Full moon                         0.1
Quarter moon                      0.01
Moonless clear night sky          0.001
Moonless overcast night sky       0.0001

LUX (architectural recomendations)
2000            conservation laboratories in galleries and museums
1000            100-watt bulb from ceiling to desk (1.5 - 2 meters)
750            drawing boards in drawing offices
500            desktops in reference library reading room
500            car showroom
500            100-watt bulb from ceiling to floor (3 meters)
200 - 400      Indoor office
300            domestic kitchen work surface
 50            cinemas, at seat level (enough to see and move safely)
 10            campfire

SOURCE               LUX PER WATT (on 1m sq and 1m distance)
Candle (equivalent)                     0.01
Oil Lamp (equivalent)                   0.03

Edison lamp          (1879)             1.4
Carbonized bamboo    (1879)             2.0
Carbonized cellulose (1891)             3.0
Metalized (Gem)      (1905)             4.0
Drawn Tungsten       (1911)            10.0
60W Tungsten C.C.    (1968)            14.7
Filament Lamp        (1970)           10 - 18
Tungsten Halogen     (1980)           17 - 22
Stage/Studio Lamps   (1980)           20 - 40

Cooper-Hewitt Lamp   (1901)            13.0
Mercury Lamp (modern)                 55 - 60
Fluorescent Lamp     (1938)           65 -100
Metal Halide Lamp                     85 -120
HPS Lamp                              80 -140
LPS Lamp                             120 -200

  On the last table (above) a 40 watt bulb (filament lamp) would
produce 400-1800 LUX a 1m distance.


So the question remains. How much light from a magical fire. My approach yeilds very low numbers. Very soft lights, almost twighlight, result.

10  =   Average person's Strength
4  =   damage from standing in a magic fire
3  =   number of turns to burn to death

Or put another way, we are talking about a fire that kills in fifteen seconds. So now I cast about to find something that burns that hot, that fast, and borrow its LUX output. Wouldn't you know it, but the only thing I find that fits the bill is spontaneous combustion. Something which there is almost no hard scientific data on. But at least it fits nicely into the fantasy genera. Spontanious combustion is defined as the tempurature were a material burns without external oxygen and provides it's own fuel.

celcius      material spontaniously combusts
 230            linseed oil
 200            leaves
 159            wood
 140            drying oil paints
 100            green hay
  95            cotton
  65 - 121      animal feed
  30 - 40       damp coal

Well, it turns out that things that burn hot tend to produce less light. The energy is converted to heat, not light. linseed oil produces fewer LUX than coal. So if a magical fire burns exceedingly hot, one could reason that almost no light is produced. Now for the pseudo science. Here are the various temps and times for reducing a human body to ash. This info varies wildly, depending on who is making the claim and what kind of equipment they are using.

  2,500 degrees                   3 hours

"Medicolegal Investigation of Death" by Werner Spitz and Russell Fischer (1980)
  1600 - 1800 degree              1 hour

"the candle effect" by D.J. Gee (1965)
    95 celcius                    8-24 hours

In conclusion: At these tempuratures hours are required. To do the same work in a quarter of a minute would require most all the energy to go into heat and not light. Magical fires may produce almost no light at all. In fact they may appear dark, even black, considering the supernatural temps involved. I would go with 0.00001 LUX. Darker than a moonless overcast night sky.

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