Canon i865 B&W prints as Sepia

Gary Dingle

When I print a 256 grey scale picture with the printer driver settings
as:
Plain Paper / Standard ... the result is a B&W print (OK)
Plain Paper/ High ... the result is more of a sepia tone
Both these settings have the print driver set to color print (GS box
not checked).
If I then check the GS box the High print quality prints as B&W OK. I
don't want to do this, as I have colour images in the document/pages I
wish to print.
I'm sure I've mixed B&W and Colour images in a document previously &
the print has been OK.
Nozzle check print appears to be OK.
Printing colour appears to be OK.
Anybody have a clue what may be the problem?
Thanks
Gary