- Quick Color Facts -
Much more complete information on light and color is in our ebook
Please also see our free sample chapter on 3D scene lighting
Color Wheel
12 Hue Color Wheel
From 'Art Head Start' by jim coe
Quick Color Facts
A color has 3 attributes:
- Hue -
Frequency of the light energy.
Red is the lowest humanly visible frequency and Violet is the highest.
Hue is what people usually mean when they say "color".
- Saturation -
Is purity, or being free of other Hues mixed in.
- Value -
Brightness, independent of Hue or Saturation.
- Primaries -
The Additive (light mixing) Primaries are Red, Green and Blue.
'Primary' means that any other color can be derived by mixing only these three.
- The Color Compass -
I think the Color Wheel should be called a "Color Compass", because it's useful to think of the Hues as measured by degrees around a circle.
- The Color Tree -
A Color Wheel is useful, but demonstrates only 1 of the 3 color attributes. Instead, a Color Tree maps each of the 3 color attributres to one of the 3 dimensions.
6 Hue 3D Color Tree by jim coe
Color Mixing
Additive mixing of Red, Green and Blue spot lights
From 'Art Head Start' by jim coe
- Light Mixing is called 'Additive Color' -
Above is an accurate simulation of what actually happens when you shine 3 saturated light sources of equal brightness onto a white screen. This is the 'Additive Color' notation system usually used for photography and computer graphics, where light sources of different hues are mixed.
Color Absorption
Subtraction of hues from white light by pigments
From 'Art Head Start' by jim coe
'Subtractive Color'
When pigments absorb some colors and reflect others, we call it 'Subtractive Color'. This 'Subtractive Color' notation system is usually used where paints and printing are involved. Some hues are subtracted from the white light (a mix of all hues) illuminating an object by pigments on or in that object. Other hues are reflected, to our eyes, giving the object its 'color'.
Human sensitivity to Electromagnetic Radiation
The known electromagnetic energy spectrum
From 'Art Head Start' by jim coe
- The Human Radio Receiver -
Did you know that you are an organic microwave receiver? Yes, light is Electromagnetic radiation energy, exactly like radio, television or radar radiations, but way up in the higher microwave frequencies.
- There's that scary word again -
Don't let that word 'radiation' scare you. Anything that propagates through space is properly said to be radiating. It just means 'spreading out'.
Because our science education has become so poor, journalists don't know to point out that all 'radiation' is not necessarily the dangerous 'ionizing radiation'. Electromagnetic radiation of a high enough frequency, and with a long enough exposure time, is powerful enough to modify some of the atoms you are made of, 'ionizing' them. That amount of energy delivery starts with short wave (upper) Ultraviolet (which is what sun block lotions are all about) and gets stronger as frequency increases.
end
Reference article by jim coe © jim coe 2006