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Author Topic: What is a pigment and how does it create color?  (Read 2002 times)

Offline EatsRainbows

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What is a pigment and how does it create color?
« on: 19/12/2009 08:56:11 »
I read somewhere on here (sorry cant remember where now!) that there is no such thing as a "white pigment" in relation to animal fur. There is however brown, black etc pigments (referred to in my genetics lectures covering inheritance of coat color in cats) that, if memory serves me right are created by particular enzyme pathways causing particular pigment production.

White only occurring due to reflected light, but other colors occurring due to presence of a 'pigment' for that color, got me wondering, is a 'pigment' actually something  that absorbs a particular wavelength and thereby causing an animals fur to be perceived as a corresponding color? If yes, then does this apply to all other colors we perceive, ie they are all due to some substance absorbing that wavelength? If no, then how exactly is color 'created'?


 

Offline EatsRainbows

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What is a pigment and how does it create color?
« Reply #1 on: 20/12/2009 06:29:48 »
I think i have answered my own question... Wiki is my God! lol Thought I'd pop it up here in case anyone doesn't know and is interested....  this should be in physics  :P

It seems that yes, perception of color is sometimes due to a pigment or other molecules that also reflect and absorb specific wavelengths but one way or the other color is always due to the wavelength of light that has been reflected? So I think that a red flower must be red because it reflects red light?

From what I've read it appears that some things only reflect light and don't actually absorb any and this is what determines color. what then is the purpose of a pigments role in absorbing light other than for photosynthesis? It would seem sufficient for everything just to reflect all light unless it has some need for the light for energy purposes.... i suppose if all light was reflected then everything would be the same color and so the 'purpose' may simply be that this is how life has evolved, colors are used by animals for many purposes.....?

Quote
Pigments appear the colors they are because they selectively reflect and absorb certain wavelengths of light. White light is a roughly equal mixture of the entire visible spectrum of light. When this light encounters a pigment, some wavelengths are absorbed by the chemical bonds and substituents of the pigment, and others are reflected. This new reflected light spectrum creates the appearance of a color

Other properties of a color, such as its saturation or lightness, may be determined by the other substances that accompany pigments. Binders and fillers added to pure pigment chemicals also have their own reflection and absorption patterns, which can affect the final spectrum.
http://en.wikipedia.org/wiki/Pigment

Quote
Biological pigments, also known simply as pigments or biochromes[citation needed] are substances produced by living organisms that have a color resulting from selective color absorption. Biological pigments include plant pigments and flower pigments. Many biological structures, such as skin, eyes, fur and hair contain pigments such as melanin in specialized cells called chromatophores

All biological pigments selectively absorb certain wavelengths of light while reflecting others. The light that is absorbed may be used by the plant to power chemical reactions, while the reflected wavelengths of light determine the color the pigment will appear to the eye.
http://en.wikipedia.org/wiki/Biological_pigment

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The color of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Physically, objects can be said to have the color of the light leaving their surfaces, which normally depends on the spectrum of the incident illumination and the reflectance properties of the surface, as well as potentially on the angles of illumination and viewing. Some objects not only reflect light, but also transmit light or emit light themselves (see below), which contribute to the color also.
http://en.wikipedia.org/wiki/Structural_color#Structural_color
 

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What is a pigment and how does it create color?
« Reply #1 on: 20/12/2009 06:29:48 »

 

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