As I understand it one black cartridge (usually the bigger one of the two) is used exclisively for text printing, the other black is used combined with the cyan, magenta and yellow to produce the range of tones and hues for colour printing.
The Evil Within 2 review-in-progress
InVision Studio takes on Adobe XD and Sketch
iPhone X news: Release date, price, new features & specs
Comment transformer un iPhone en borne Wi-Fi ?