I'm creating a design sheet, and I have a standard white background with some parts of it coloured as a feature. I have bodies of black text on the page which sometimes overlaps the white and coloured areas. I need it so where the text is over the default white it stays black, however where it overlaps the coloured background it changes to white. I've tried messing around with the various layer modes including difference, but none seem to give me this result. Any help would be much appreciated.
If you make sure everything is on separate layers, then this is a fairly easy task. You can use the arrangement of the layers and clipping to achieve your desired result.
Here I have a white background layer, above that a black text layer, above that a coloured drawing on a transparent layer, and above that a duplicate of the text layer, but with the text colour changed to white. The top white layer is then clipped to the colour layer.