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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?
Erol,
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
Illuminence
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.
Crematorium
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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