Now let’s focus on… The visible spectrum The visible spectrum –Light and pigment

Visible light is that portion of the electromagnetic spectrum which stimulates the retina of the human eye. Visible spectrum wavelengths range from about 400 nm (violet) to 760 nm (red). Light travels at about 3 x 10 8 m/s through empty space and slightly slower through air. Remember that for all waves, v = f.

COLOR Materials may be classified as: transparent - readily transmits light; can clearly see objects through them translucent - transmits, but diffuses, light; cannot see objects clearly through them opaque - transmits no light; cannot see through them

WHITE light is a combination of ALL the colors of the visible spectrum. Red, orange, yellow, green, blue, indigo, violet is the order of increasing frequency or decreasing wavelength. Frequencies directly above this spectrum are ultraviolet. Frequencies directly below this spectrum are infrared.

Mixing colors There are two ways to mix colors There are two ways to mix colors Mixing colors of LIGHT Mixing colors of LIGHT –Additive mixing Mixing colors of PIGMENT Mixing colors of PIGMENT –paint, ink or dyes –Subtractive mixing

Mixing Light Used in computer screens, TVs, and stage lighting Used in computer screens, TVs, and stage lighting The primary colors are The primary colors are –Red, Green and Blue –(Roy G. Biv) The secondary colors are The secondary colors are –Cyan, Magenta and Yellow

Mixing Light - Additive

Mixing Light Yellow Magenta Cyan White Complimentary colors are ACROSS from each other Red-Cyan, Blue-Yellow, Green-Magenta When complementary colors are mixed, they form white light.

Light – Additive Process Called “additive” process because new colors are formed by the addition of more than one color signal. Called “additive” process because new colors are formed by the addition of more than one color signal. The additive primary colors are RED, GREEN, and BLUE. The additive primary colors are RED, GREEN, and BLUE. If the signal is equal parts red, green, and blue we perceive this is white light. If the signal is equal parts red, green, and blue we perceive this is white light.

Mixing Light - Additive

Pigments – Subtractive Process Dyes and pigments subtract out colors by absorbing some colors and reflecting others. The primary pigments are cyan, magenta, and yellow. These colors are the result of the absorption of one of the primary colors of light.

Pigments – Subtractive Process

Black is made when no light is reflected. If you add magenta, cyan, and yellow together, they absorb all light so it looks black. Black is made when no light is reflected. If you add magenta, cyan, and yellow together, they absorb all light so it looks black. To make green paint you need to absorb red and blue light and reflect green light. So you mix cyan, which absorbs red, and yellow, which absorbs blue. To make green paint you need to absorb red and blue light and reflect green light. So you mix cyan, which absorbs red, and yellow, which absorbs blue.

Making Green Paint

Mixing Pigments