Provided is a page expansion and printing method for a pagewidth inkjet printer. The method features the step of receiving a page description having a bi-level black layer and a contone CMYK (Cyan Magenta Yellow black) layer from a host and storing said page description in a memory. The method also includes the steps of decompressing the respective layers in parallel, halftoning the contone CMYK layer to bi-level CMYK, compositing the bi-level black layer over the bi-level CMYK layer, and transmitting the image to a memory buffer for printing by the pagewidth printer.