Creating RGB composite from acetate sheets

HI DC

Just going through your excellent book. Will be trying the "Breaking out Components" chapter soon.

I wanted to demonstrate how printed images are made up of CMYK inks stamped onto the white paper (I am a teacher). I was able to split channels, then duotone, then greyscale to get seperate files which I then printed on a transparency sheets on colour printer. When I lay the 4 sheets on each other the composite image is similar to the original image. The colours are correct regardless of whether you look through the sheets or lay them on a white paper to emulate printing.

I wanted to do the same for RGB. Created Red, Green and Blue prints on acetate using the same process. However, the red bus in the image turns green in the composite! I have also made grey scale prints of each channel and thought of shining coloured lights through them. Then I read your book.

Any ideas where I am going wrong and what should I be doing? All help appreciated.