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Author Topic: fading colours  (Read 5738 times)

paul.fr

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fading colours
« on: 26/03/2007 18:36:58 »
having just fetched my washing in, i have a quick question.

How long would i have to leave my clothes hanging in the sun to notice that they had faded, and why is it that sunlight causes colours to fade?

does the heat ironing play a bigger part in fading the colour of clothes than sunlight?
« Last Edit: 26/03/2007 20:48:56 by paul.fr »


 

Offline lightarrow

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fading colours
« Reply #1 on: 26/03/2007 22:25:33 »
How long would i have to leave my clothes hanging in the sun to notice that they had faded?
Very difficult question, it depends mostly on which substances the pigments are made of.
Quote
why is it that sunlight causes colours to fade?
Many pigments are made of unstable organic substances. They can absorb photons and transform into other (usually more stable) substances.
Quote
does the heat ironing play a bigger part in fading the colour of clothes than sunlight?
Don't know. I presume even here that it depends on which are the substances involved.
 

paul.fr

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fading colours
« Reply #2 on: 26/03/2007 22:35:57 »
Very difficult question, it depends mostly on which substances the pigments are made of.

would the nature of the material also be a factor, if it was say cotton or nylon for example?
 

Offline Karen W.

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fading colours
« Reply #3 on: 27/03/2007 03:32:39 »
I forgot a green towel thick eqyptian Cotton on the line, Hunter Green in color! I forgot it for about two weeks when I retrieved it from the the line the sun rise side was still vibrant but the side exposed to the afternoon sun on the sunset side was very faded!!! This was in July I would say end of July!
 

paul.fr

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fading colours
« Reply #4 on: 27/03/2007 04:49:59 »
I forgot a green towel thick eqyptian Cotton on the line, Hunter Green in color! I forgot it for about two weeks when I retrieved it from the the line the sun rise side was still vibrant but the side exposed to the afternoon sun on the sunset side was very faded!!! This was in July I would say end of July!

Interesting.
 

Offline Karen W.

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fading colours
« Reply #5 on: 27/03/2007 05:45:45 »
I wondered if it had to do with the intensity of the afternoon sun being hotter and the days being longer and all!
 

another_someone

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fading colours
« Reply #6 on: 27/03/2007 07:53:26 »
The most damaging radiation for dyes (as for most other things) is UV radiation.  That which you feel as heat is mostly infra red, and the two do not necessarily (although sometimes they may) correlate.
 

Offline anthony

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fading colours
« Reply #7 on: 16/04/2007 13:12:08 »
Mostly this is some photochemistry. Dyes absorb light. If they didn't they wouldn't be very good dyes. Every time the dye molecule abosrbs light there is a chance it will decompose, depending on the enrgy of the light and the structure of the compound, yada, yada. Higher energy light, like that from the sun - lots of ultraviolet, is more likely to make the dye decompose and fade.

The effect of the heat is minor, clothes do not fade in the airing cupboard.

Many manufacturers now add compounds that prevent fading, by absorbing the energy from the light, directly from the dye molecule, before it can decompose.

Of course, your washing powder is also making your clothes fade, particulalrly if it's a whites variety as they contain the most powerful bleaches. That's chemical decomposition and probably has more effect than line drying.

If you want to protect your clothes, dry them behind a polycarbonate screen, that will absorb the UV. The infrared will dry your clothes in the meantime. I've posted on UV and polycarbonate before.
 

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fading colours
« Reply #7 on: 16/04/2007 13:12:08 »

 

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