Emu XL-7 & MP-7 User's Group

It is pretty cool. For example a white LED is actually blue and 
yellow, not an even distribution of colors. 

Ezra

--- In xl7@y..., Aaron Eppolito <aarone+list@e...> wrote:
> This is totally off topic, but it's something that always intrigued 
> me...  Read on if you're interested in human color perception, 
> otherwise, feel free to toast this one!
> 
> erik_magrini@B... wrote:
> 
> > My second thought was to take blue film and lay them over the 
LED's 
> > inside the case (Red+Blue=Purple, which would be cool too!).  
Sadly, 
> > this didn't work either as the RED is just too bright, 4 layers 
of 
> > blue gel film did nothing to change the shade at all.  Oh well, 
it was 
> > a cool idea none the less!
> 
> Unfortunately, that'd actually be Red-Blue=Red.  Starting off with 
a 
> pure red (I think somewhere around 730nm in our case) doesn't leave 
any 
> other colors to filter out.  This is one of the fallacies of the 
grade 
> school teachings we all get (though try and explain spectral 
analysis to 
> a 6 year old...)  Things that look the same color to our eyes are 
not 
> necessarily the same color.  Our eyes are sensitive to three 
distinct 
> colors (RGB) out of a continuous spectrum.  When you see yellow, 
it's 
> really that you're seeing about the same amount of red and green, 
which 
> your brain interprets as yellow.  Computer monitors don't produce 
yellow 
> (or white, or orange, or purple, etc), they just fool your eye into 
> thinking that it sees yellow.
> 
> So in the above case, your eye can't tell that it's a pure red from 
a 
> red lamp for example which may look like the same red, but not be a 
pure 
> color (i.e. containing a whole lot of wavelengths, just centered 
around 
> that frequency).  That's why most gels in catalogs come with a 
filter 
> spectrum so that you can know how it will interact with other gels.
> 
> Anyway, sorry for the rambling, I just always thought how we 
perceive 
> things is a cool subject...
> 
> -Aaron