Note that this is boilerplate text.
If you give complete and detailed information about your setup and the issue at hand,
such as your platform (Mac or Win),
exact versions of your OS, of Photoshop (not just "CS6", but something like CS6v.13.0.6) and of Bridge,
your settings in Photoshop > Preference > Performance
the type of file you were working on,
machine specs, such as total installed RAM, scratch file HDs, total available HD space, video card specs, including total VRAM installed,
what troubleshooting steps you have taken so far,
what error message(s) you receive,
if having issues opening raw files also the exact camera make and model that generated them,
if you're having printing issues, indicate the exact make and model of your printer, paper size, image dimensions in pixels (so many pixels wide by so many pixels high). if going through a RIP, specify that too.
someone may be able to help you (not necessarily this poster).
a screen shot of your settings or of the image could be very helpful too.
Please read this FAQ for advice on how to ask your questions correctly for quicker and better answers:
I am not sure I understand your objective and whether it is significant that the tan color you object to is in fact the foreground color, but on the off chance you are looking for an effect such as the one shown below, it may be achieved by making a selection that bisects the image and Image > Adjust > Inverting it,,, then adding a type layer set to Difference. Difference will handle the black-to-white type split automatically. I apologize if I misunderstood your intention.
It seems the problem was with the CMYK colour space I was using. After changing it to RGB, it went away. Not sure why, however. Thanks and sorry if I wasn't super clear in my question.