Color

What is Color? The color of an object is produced by light frequencies that are emitted or reflected off of objects and perceived by our eyes. Other organisms, including people with defective color vision, can not see some or all colors.

Color Blindness Checks

The Spectrum Using a prism, light can be broken up into a spread of colors called a spectrum. In order these colors are red, orange, yellow, green, blue, indigo, and violet (ROYGBIV)

White and Black White light, like sunlight, is a combination of all colors together. White objects appear white because they reflect all colors. White is not a color but the combination of all colors. Black is also not a color but the absence of all colors. Objects appear black because they absorb light of all visible frequencies. (Black objects don’t absorb all light or you would not be able to see them)

What color is it? The color of most objects is due to the way they reflect light. When light hits objects, the electromagnetic energy causes the atoms in the object to vibrate and absorb some energy while reflecting other energy. When white light falls on a rose, the rose absorbs some light and reflects light that makes it look red.

Transmission The color of transparent objects depends on the color of light it transmits, or lets through. The material in that selectively absorbs light is called pigment. Green stained glass looks blue because it absorbs all colors, and lets green pass through.

Sunlight Sunlight contains all colors of light mixed together. Yellow-green light is the brightest part of sunlight. Because of this, humans are more sensitive to yellow green than to other colors.

Primary & Secondary Colors Light can be broken up into 6 basic colors, 3 primary colors and 3 secondary colors. The three primary colors are red, blue, and green. All other colors can be made using these three. Red, Blue, and Green are also called additive primary colors The secondary colors are made by combining the 3 primary colors Red + Green = Yellow Red + Blue = Magenta Blue + Green = Cyan

Color Wheel Colors across the wheel from one another are complimentary colors. Mixing any 2 complimentary colors gives you white. Yellow + Blue = White Magenta + Green = White Cyan + Red = White

Pigments The colors you see in paints and dyes are called pigments. Mixing pigments is not the same as mixing light. Pigments absorb some light and reflect other, so when you mix pigments you increase the types of light that you are absorbing. The subtractive primary colors are magenta, cyan, and yellow. Mixing complimentary pigments will give you black.

Why is the Sky Blue? As light enters our atmosphere, the atoms cause it to scatter in different directions. When the layer is thinner higher frequencies scatter more. The ozone absorbs most UV rays. Violet light, and blue light are scattered the most by the molecules. Since our eyes are more sensitive to blue light that is what we see.