Light and Dark
Measures of Luminescence
The elements of Light and Dark have a simple relationship – the more Light, the less Dark, and vice versa. There are several ways of measuring the Luminescence provided by this interaction. One measure is the so-called 'percentage of Light', which is commonly used by Celestial Adepts. Another, more mundane, measure is the foot-candle. One foot-candle is the amount of light shed by a normal candle at the distance of one foot. These two methods have a natural logarithmic relationship where 10% more light is 10 times as many foot-candles -- except at extreme light levels, where the 'percentage of Light' measure is distorted by the limits of Elven vision. The following table describes the light level in many common situations.
Light Table
This table differs slightly from the table in the Celestial College. That table is the correct and approved 'rule' for Lighting Modifiers.
| Light | Dark | ft-candle | Natural Conditions | Artificial Conditions |
|---|---|---|---|---|
| 100% | 0% | 20,000+ | Absolute Light | |
| 99% | 1% | 10,000 | Noon in a desert | |
| 95% | 5% | 5,000 | Summer Clear Day, Direct Sunlight | |
| 90% | 10% | 2,000 | Autumn Clear Day | Rank 15 Light |
| 85% | 15% | 1,000 | Full Daylight, Summer Overcast day | |
| 80% | 20% | 300 | Autumn Morning, Light cloud; Mist | Rank 10 Light |
| 70% | 30% | 50 | Winter Overcast day, Bright day in a forest | |
| 60% | 40% | 10 | Very dark day; Driving rain; Smoke/Fog | Inside on overcast day, Brightly lit Interior |
| 50% | 50% | 1 | Twilight, Major Storm | Shuttered room in day, Lamp-lit Interior |
| 40% | 60% | 1/10 | Deep Twilight, pre-Dawn | 1 candle at 3', Bonfire at night, Rank 0 Dark |
| 35% | 65% | 1/30 | Full Moon on a clear night | Torch-lit Chamber |
| 30% | 70% | 1/100 | Gibbous Moon | Bright fire at night |
| 25% | 75% | 1/300 | Night in a town | Campfire at night |
| 20% | 80% | 1/1,000 | Quarter Moon | 1 Lantern Underground, Rank 10 Dark |
| 10% | 90% | 1/10,000 | Moonless clear night sky, Stars, Rank 15 Dark | 1 Torch Underground |
| 5% | 95% | 1/100,000 | Moonless overcast night sky | Single Candle Underground |
| 1% | 99% | 1/1,000,000 | Midnight in a storm, Deep Underground | Underground, no lights |
| 0% | 100% | 0 | Absolute Darkness |
Changing Light Levels
As magical Light or Darkness spells change the Light level by 2%/Rank: each additional rank of Light increases the luminescence (in foot-candles) by 60%, as if the light source were 25% closer; 3 ranks makes it 4 times brighter, or as if the light source was twice as close; and 5 ranks makes it 10 times brighter, or as if the light source was 3 times closer. This relationship fails for Light (or Dark) levels above about 90%.
