Color

•Isaac Newton first studied light when he used a piece of glass and first saw the color spectrum.

•The visible/color spectrum is the ordered arrangement of colors by wavelength and frequency

Spectrum

Color by Reflection

• Different objects reflect (if material is opaque) and absorb (if the material is transparent)

Color by Transmission• The color of a transparent

object depends on the color of the light it transmits

• The material in glass that selectively absorbs colored light is pigment.

• Glass is colorless since it transmits all visible frequencies.

(examples-the 3 pixels in your TV)

•Secondary-the result of mixing 2 primary colorsRed + Blue = MagentaBlue + Green = CyanRed + Green = Yellow

Light-there are primary and secondary colors of lightPrimary-Red, Blue, Green

•Adding colors of light is called Color by Addition

•White-addition of all colors of the visible spectrum, or by adding the 3 primary colors

•Black-absence of light, all 3 lights are blocked

ADDITION OF PRIMARY COLORS

• When paints or dyes are mixed, the mixture absorbs the frequencies of the paint or dye

• Complementary colors of light-two colors which when added, create white light

• Blue + Yellow = White

• Red + Cyan = White

• Green + Magenta = White

So…yellow light is the complementary color to blue light

•A Pigment is a colored material that absorbs certain wavelengths of light (certain colors) and transmits or reflects others---Think PAINT

•Primary Pigment-A pigment that absorbs only one primary color from white light

Yellow (absorbs blue light)Cyan (absorbs red light)Magenta (absorbs green light)

•Secondary Pigment-A pigment that absorbs two primary colors and reflects one

Red (absorbs green & blue)Blue (absorbs red & green)Green (absorbs red & blue)

PRACTICE

Answers to Practice

• Addition of Primary Colors

• Red + Green = Yellow

• Red + Blue = Magenta

• Blue + Green = Cyan

•Color by subtraction~the pigment is ‘taking out’ / ‘subtracting’ / ‘absorbing’ a color of light•Complementary Pigments-two colors that when added, will absorb all colors of the spectrum (‘black’ pigment is made) minimal/no light is reflected

•Think Mixing Paint…yellow + blue = black cyan + red = blackmagenta + green = black

PRACTICE

Answers to Practice

• Practice A- Magenta is red + blue. Blue is subtracted (absorbed) so that leaves red, shirt appears red

• Practice B-red is a primary color, blue is subtracted (absorbed) so it is not present, so shirt appears red

• Practice C-Blue is a primary color, blue is subtracted (absorbed) so no color is left, shirt appears Black

Why?

• …is the sky blue

• Blue is scatted the most during the middle of the day, due to its high frequency and low energy

• …are sunsets red

• Red, orange, and yellow are scattered more during this time, so red is refracted more, so red, orange, etc if seen

•Do problem set in class