The Neutral Grays setting determines the method that the printer uses to create gray colors in text, graphics, and photographs.
Two values are available for the Neutral Grays setting:
||Black Only generates neutral colors (grays and black) by using only black toner. This guarantees neutral colors that do not have a color cast.
||4-Color generates neutral colors (grays and black) by combining all four toner colors. This method produces smoother gradients and transitions to non-neutral colors, and it produces the darkest black.
Some software programs convert text or graphics to raster images. In these cases, the Photographs settings also control text and graphics.
HP Color Laserjet 2605 Neutral Grays