Johnny G Junior's NoteBook Treasures: July 2009

Saturday, July 18, 2009

Terms and Light Theory

Notes of Light Theory from various sources.

Inverse Square Law:
Easily explained by an example of fire. If you walked slowly towards a fire, you would feel yourself getting gradually hotter. However the rate at which you would get hotter would NOT increase uniformlyas you approached; you would feel a slow increase early on, but as you got closer and closer to the fire, you'd feel a very rapid increase in heat. This is the inverse suqre law in action. The way in which light fades from its source also obeys this law.

Lights luminosity does not change; it alters in lights brightness as perceived by the viewer. As light travels further away from its source, it covers more area and this is what makes it lose its intensity, fading according to the reciprocal of squares of the distance. DAMN!

Laws of Reflection:
how light reflected from a surface. Tge abgke if reflection equals the angle of incidence, which is measured relative to surface normal at the point of incidence. The simulation of this law in cg takes place using a rendering process called RAYTRACING which simulates accurate reflections and refractions.

Refraction:
How light bends which concerns tranparent and semi-transparent objects. Think pencil in a cup in water... This number is calculated by taking the speed of light in a vacuum and dividing it by the speed of light in a material. Light never travels faster than in a vacuum, this value never goes below 1.0. As the value increases, the amount of distortion increases.


Index of Refraction (IOR)
Material
Air................................ 1.0003
Alcohol .......................... 1.329
Water..............................1.330
Ice....................................1.333
Glass................................1.500
Emerald..........................1.570
Ruby................................1.770
Sapphire..........................1.770
Crystal.............................2.000
Diamond..........................2.419

Wednesday, July 15, 2009

Color Temperature Chart

COMMON COLOR TEMERATURES. For those looking at lighting in 3d.

: ) ENJOY.

Candle Flame ..............................................1900K
Sunlight:Sunset or SunRise..........................2000k
100-Watt household Bulb.............................2865k
Tungsten Lamp (500w-1k)............................3,200k
Flurescent Lights ............ ............................3,275 - 34,000k
Sunlight: Early Morning/Late afternoon.......4,300k
Sunlight:noon..............................................5,000k
Daylight.......................................................5,600k
Overcast Sky................................................6,000 - 7000k
Summer Sunlight plus blue sky....................6.500k
Skylight.......................................................12,000-20,000k