um it sems that you have the slice layer view on perhaps when you hide the slices you will have a complete grey... with no un-wanted cast... also have a look at the proof coulour set up you have... you may have photo shop viewing the greay space in cmyk or something heav a look at the proof set up... perhaps. not dure what you mean by swatch but normally the colour you pick to be your forground will become your foreground...