At Macworld Expo last week in San Francisco, we got a little tip from the folks at Hewlett-Packard about the Photosmart Pro B9180 and B8850 printers, as well as the wide-format Designjet Z2100: when you’re printing on matte or fine-art media, the printer uses both the photo and matte black inks, in addition to the gray ink. The end result is that you get deeper blacks, and much better tonal range in the shadows, especially when working with black-and-white images.
When you’re printing on glossy and semigloss papers, the matte black ink isn’t used, but the nature of the paper and the ink mean that getting rich, deep blacks is less of an issue.
This is definitely one of the reasons that HP’s black-and-white output looks comparable to that of Epson’s Stylus Photo R2400, which uses two lighter shades of black in addition to the photo and matte black inks.
And, if you’re printing on HP’s high-end Designjet Z3100, which has photo black, matte black and two gray inks, you’ll get a quadtone print when using matte or fine-art papers, which is quite nice.