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Location:
Adelaide
Registered:
September 2003
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refracting coloured light (for the year 12 physics maniacs)
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Mon, 06 June 2005 12:48
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Hi guys i am just after either a web site or someone with knowledge on how to get light to display different colours when shone through a filter.
ie if you had a red light and shone it through a blue filter the colour would appear like...
if there is a simple colour wheel that exists or something similar, i would be pretty grateful.
note this is a different colour wheel to a standard one utilising pigments.
basic primary, secondary and tertiary colours with primary, secondary, and tertiary filters should get me virtually every solution i am after.
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Location:
Sydney
Registered:
September 2004
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Re: refracting coloured light (for the year 12 physics maniacs)
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Tue, 07 June 2005 03:27
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| barned01 wrote on Mon, 06 June 2005 22:48 |
ie if you had a red light and shone it through a blue filter the colour would appear like...
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PURPLE!  and I didn't even do physics!  
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Location:
Sydney
Registered:
September 2004
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Location:
Adelaide
Registered:
September 2003
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Re: refracting coloured light (for the year 12 physics maniacs)
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Tue, 07 June 2005 11:31
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ok i can suss out the basic in my head like if you have a white light then place red filter in front off the light, then you will see a red light through the filter.
i get a bit lost however after the three primary colour filters.
i have a funny feeling, i don't know why but if i had a red light and i put a blue filter in front of it then the light won't actually show up as purple but will instead appear as a "dark" light.
for instance simple ascii diagram. we go on the theory light is made of green, blue and red light (abviously lots more but i am trying to maintain simplicity)
.............r............b
rrrrrrrrrr->.r.rrrrrrrr->.b *
.............r............b
gggggggggg->.r.*..........b
.............r............b
bbbbbbbbbb->.r.*..........b
.............r............b
as the white light (made of red green and blue light on the left) enters the red filter the green and blue light of the spectrum get absorbed but the red part of the spectrum can pass through, so now we see red light, but if i place a blue filter in front of the red light, the red part of the spectrum becomes absorbed as well and now the light "shouldn't" be visible anymore.
my mind is interpreting this differently to getting a red opaque pigment and blue opaque pigment, combining them together and shining a white light onto it (which will indeed reflect as purple so thu187 you are correct for reflecting white light from opaque surfaces), but i don't think that it works the same for coloured light and their respective filters.
my interest in this is say you have aqua and orange light and other tertiary and secondary coloured lights like that, is it possible to place a filter over those lights to make it appear say purple and pink or other such colours.
edit:the dot's in the ascii picture are supposed to be blank but the post didn't display the pic correctly so i had to pot in dots instead.
[Updated on: Tue, 07 June 2005 12:14]
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