The assumption that paper is white is, of course, faulty. So-called white papers come in varying shades of white and degrees of brightness. Then there are coloured papers and transparent media, such as self-adhesive vinyl. Producing “white” is a real problem for inkjet printers.
That’s why I’ve always wondered why inkjet printers don’t include a white ink. Even my HP Z3100 with 12 inks doesn’t have white. A white ink makes so much sense to me. It would extend the gamut, provide more accurate colour profiling and open up more creative options.
Adobe InDesign understands there is a difference between “White” and “Paper”. Too bad my printer doesn’t. Apart from the extra cost (which I don’t think would deter me), is there a good reason for this?