Here ’ s Looking at hue, Kid

You have probably noticed that the COLOR of an object can appear different under different lighting conditions.

These differences in color are to due differences in the REFLECTING and light- absorbing properties of the object being illuminated.

Color by Reflection Most materials absorb some frequencies of light and reflect others. If an object absorbs all frequencies of light except red then it will appear red or it reflects red. Objects which are white reflect all colors of the spectrum. Objects which are black absorb all colors of the spectrum (thus black objects left out in the sunlight become hotter than other objects).

Sunlight is an example of what is considered WHITE light. A Bug’s Life!

If sunlight is considered white light, why does it look yellow? Two reasons: –Sunlight’s greatest intensity is right in the middle of the color spectrum – R O Y G B I V –Out of Yellow, Green and Blue we are most sensitive to yellow!

When a ray of sunlight is DISPERSED, as Newton first accomplished in 1666 using a prism,

you can see what Newton named the color SPECTRUM which is composed of

RED ORANGE YELLOWYELLOW GREEN BLUE INDIGO VIOLET light. YROY G BIVYROY G BIV

The ADDITIVE PRIMARY COLORS OF LIGHT are red, green, and BLUE.

When these colors of LIGHT are mixed (in equal amounts), white light is produced

yellow along with the ADDITIVE SECONDARY COLORS OF LIGHT which are cyan, yellow, and MAGENTA.

Any two colors which combine to form white light are called COMPLEMENTARY colors. Yellow + Blue = White Magenta + Green = White Cyan + Red = White

yellow The SUBTRACTIVE PRIMARY [PIGMENT] COLORS are cyan, yellow, and MAGENTA.

Why is paint color different from light color? If you have ever played with paint you know that adding yellow and blue paint did NOT give you white paint... In fact the more paint you add the blacker it gets. SO WHAT MAKES THE DIFFERENCE?

Paint and dyes are made up of little particles of pigment that absorb different frequencies of light. Blue paint reflects mostly blue light but it does reflect some violet and green; it absorbs red, orange, and yellow light. Yellow paint reflects mostly yellow, but also red, orange and green; it absorbs blue and violet light. If you mix blue and yellow that means that it will absorb red, orange, yellow, blue and violet... which leaves green.

When these colors of PIGMENT are mixed (in equal amounts), black is produced

green along with the SECONDARY (PIGMENT) SUBTRACTIVE COLORS which are red, green, and BLUE.

How do printers print with just four colors? Color printers only have four colors (magenta, yellow, cyan and black). Each color of ink comes from a different plate, which transfers the ink to the paper.

How do printers print with just four colors? The ink is on the plate in tiny dots. The subtractive properties of the overlapping dots cause different colors to be seen.

The color spectrum is produced because light is REFRACTED as it enters a water drop or prism.

Each of the different colors of light travels at a different speed through the medium.

As each color exits the medium, it DISPERSES by a definite and predictable amount.

What color would a ripe, red tomato appear in blue light? In yellow light? Red absorbs blue and green and reflects red. So when in blue light it looks black. Yellow light is made out of red and green light. The red tomato absorbs the green part but reflects the red part and thus looks red.

Colors of the spectrum can be seen naturally as a result of DISPERSION such as --

Why Is the Sky Blue? Our atmosphere is made out of tiny little atoms and molecules. These tiny little molecules scatter high frequency light (violet/blue). This scattered light is sent out in all directions. Violet light is actually scattered more than blue but our eyes are not as sensitive to violet as blue. Clouds have many different size particles which means they scatter all the frequencies of light and thus we see WHITE.

What color of light would be most beneficial for plants? Chlorophyll in plants makes them look green. Plants therefore reflect green. Thus if you were to shine green on them they could not absorb any heat from the light. So what color should you shine on them?