Cadman,
Suggest you take 15 mins. or so to read through the info on:
http://www.digital-darkroom.com on Colour Management.
In the mean time:
The numbers in an image file do not represent specific colours. For example, 100R, 0G, 0B just means "make the brightest, most saturated red you can". It doesn’t mean a specific SHADE of red, and the red that will result will depend upon the capabilities of the device the data is being sent to (usually either a monitor or printer of some sort).
Only when coupled with an ICC profile that describes the ‘colour space’ do those numbers represent a specific shade.
If it helps you in any way here is my short "idiot’s guide to CM" <g>
There is data in a file. That data doesn’t represent specific colours UNTIL the colour space is stated (embedded profile or assign profile).
The working profile sets up the colour space you are working in, and the embedded profile allows the CM engine to convert the file data values to your working space values so those values still represent the same colour as originally indicated by the file data and embedded profile.
The monitor profile alters that data from your working space on the fly to allow the monitor to display the colours represented by the data within the working space profile.
When you print, the output profile alters the data to allow the printer to reproduce the colours represented by the data and the image profile.
The monitor profile effectively drops out of the equation when you print.
Provided the ‘translation’ from working space to monitor is correct AND the translation from working space to output device is correct, the print will match the monitor.
However, only if the translation from embedded profile to working space is also correct will the monitor and print also match the original file intentions.
For a fuller explanation, spend some 15 minutes or so over at
http://www.computer-darkroom.com 
