Bob Williams wrote:

I think the reason is, that NO combination of RGB used in sensors can
produce violet (purple?) light. The visible color spectrum is ROYGBV.
All colors between R and B can be generated by mixing appropriate
amounts of R, G, and B. But Violet is a shorter wavelength than any of
the frequencies captured by an RGB sensor. So no combination of longer
wave lengths can produce a shorter wavelength.
You can't fix it with Photoshop either because PS also uses an RGB
palette (e.g. Adobe RGB).

Wow... thank you for telling me this NOW... just today I was in the
botanic garden and had some really beautiful violet flowers which seemed
to be just blue on the camera display.
http://www.flickr.com/photos/kruemi/2349815089/
I've added some more red on my computer at home, but it's not really
near the color that they had actually.
Now that you explain it, its the reason, why it did not work.

Thank you

Marco

--
Dimage A2, Agfa isolette
http://flickr.com/photos/kruemi
http://profile.imageshack.us/user/kruemi/images