Color of Light

In order to recognize any perceptions of color, light is necessary. A green leaf appears green because the light reflects green light and all other colors are absorbed into this specific leaf.

While, white light from the sun contains all the possible color variations, human eyes are only capable of responding to certain colors and wavelength.  The ability of processing color is owing to our eye's light and color-sensitive receptors, rods and cones, and the color vision may vary between individuals as well as  species.


Yuri Endo 2012

When the red light ( from a red dot laser pointer) passes through the red gummy bears, it exits on the other side, yet when the red light is pointed at the green gummy bears, the light does not pass through.

When the white light ( from a LED light) passes through the red gummy bears, it makes them appear red . At this point,  all the colors in the visible light spectrum is absorbed except for the red. The same results can be observed from the green gummy bears, yellow and orange gummy worms. 


Yuri Endo 2012

When the narrow beam of white light passes through a glass prism, the white light is spread up into the colors of visible light spectrum which is in the same color and order as does in the rainbow; red, orange, yellow, green, blue, indigo, violet, respectively. In other words, white light is the mixture of the colors that prism separates out.

Each color has a different wave length and bend in different amount. For example, violet has the shortest wavelength and bends the most while red has the longest wavelength and bends the least.

Reference: Newton and the Color SpectrumVideo: Visible Light Spectrum, Newton's Prism Experiment


Yuri Endo 2012

>img. 1:  LED lights (with Red, Green and Blue filters) used for the experimentation
>img. 2:  RGB color addition
>img. 3:  Red
>img. 4:  Green 
>img. 5:  Blue 
>img. 6:  Red + Green = Yellow
>img. 7:  Red + Blue = Magenta  
>img. 8:  Green + Blue = Cyan
>img. 9:  Red + Green + Blue = White
>img. 10: img. 9 with an object 

Filament of the back of the light emits all the colors in the spectrum (white light).  As also seen in the previous Gummy Bear experiments, when the red filter is placed in front, only red passes through the filer absorbing the other colors and appears to give out red light. Green and blue filters react in the same exact manner. 

Red, green and blue are primary colors of light. Overwrapping the three makes white light. On the other hand, combining a pair of primary colors gives the secondary colors; yellow, magenta and cyan. For example, adding red and green makes yellow, red and blue makes magenta and green and blue makes cyan.  

As seen in the img. 10, when the object is placed in front of white light, it casts yellow, magenta and cyan shadows.  

Reference: Video: Color Addition 

No comments:

Post a Comment