I have taken some Black and white shots in Raw with my canon eos450, now they are B&W on the cameras LCD and also in the folder on my desk top but as soon as I open them they open in colour!
Any ides or why this is please.
When you shoot in RAW absolutely NO processing will be applied to the image. The sensor captures information in colour and so RAW files are in colour.
They show up in B&W in the folder preview and on the camera because there will be some stored information in the file header that you were in B&W mode so a small jpeg thumbnail would have been built in to the header that is B&W. The RAW file will never be B&W
What you've done can actually be a really good way of shooting in B&W though as, if you use live view, you get a B&W image so you can see what the shot will look like in B&W but you still get the option of a colour version. Also, you get much nicer control over the B&W conversion, especially using something like CS4 as you can play with the colour filters to change the contrast etc.