How so? The Apple's high-res graphics mode was 280 pixels wide, the standard ROM font drew characters 7 pixels wide to achieve 40 characters per line; it sounds like ScreenWriter II drew characters 4 pixels wide to achieve 70 characters per line (a bit cramped, especially for M and W, but doable). What is 'subpixel' about that?
It's not really 280 pixels wide: there are 280 addressable pixels but changing one can affect another nearby. Drawing diagonal, intersecting lines can make your blue lines green or whatever. Loosely speaking, there are 280 sub-pixels across, which works fine on monochrome monitors but on color monitors screenwriter's 70 column mode is psychedelic.
