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Non Life Sciences => Chemistry => Topic started by: Grant Langeveldt on 09/05/2011 00:30:04

Title: Why do red objects seem to fade faster in sunlight?
Post by: Grant Langeveldt on 09/05/2011 00:30:04
Grant Langeveldt  asked the Naked Scientists:
   
Hi there Chris,
 
I have searched the internet , but get many varying answers & I thought that you will answer this question correctly!
 
Why does the colour red seem to look as if it fades "quicker'' over time in the sun than any other colour? Taking a car that has red paint as an example. Is it because of the suns UV rays or the pigments?
 
I am looking forward to your answer.
 
Many thanx
Regards
Grant

What do you think?
Title: Why do red objects seem to fade faster in sunlight?
Post by: budip on 09/05/2011 01:18:52
Not all red is faded. Look at Santa Claus' clothes. Still red for years...:)

It depends. Yellow also fades, but it's difficult to detect because if it fades, it will turn to creamy white. So, not much differences noticeable. All color absorbs wide spectrum or light from the Sun. The sun's ray is polychromatics, so it consist of all visible and non-visible color. Why red color fades so fast, I believe it's because the red color components react by absorbing the blue ray, which in fact has a higher energy so that makes the red color molecules changes (degrades) from time to time.

Blue has shorter wave length, therefore higher energy. If you see in rainbow's color spectrum, red is in the complete opposite from blue or violet. From that, we can see that red will be the first "victim" among other visible color. Of course there are many ways to protect, one of example is to layer it with highly reflective material and UV protection. Just like what we all see in the traffic signal.

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