To get images in Trichrome you need to shoot 3 separate exposures through a Red, Green and Blue filter.
From there the easiest way is to scan each frame in Photoshop and combine them in a hybrid process. Although I'm sure you could do a colour matrix of each negative in analogue like a carbro?
I've been doing them for a few years, here is my blog post on how I do it:
http://photo-utopia.blogspot.com/2007/11/colour-images-from-b-film.htmlYou can get almost perfect colour with practice, but I like some movement, so things get recorded as opposite colour shadows-this is the diliberate effect you see in the background of the flower shot.
Movement in the clouds also gets recorded by each separate filter, giving the rainbow effect.
Take a look Henri Gaud's Fantastic Trichrome blog too:
http://trichromie.free.fr/trichromie/Take a look at the 3rd shot down of the beach towels with yellow, magenta and cyan shadows-wonderful.
Mark