In some systems, the space between the dots is fixed and the size of the dots varies. The larger the dots, the denser the colour. In other systems, engineers try to make the dots as small as possible and create different densities of colour by placing same-sized dots closer together or wider apart. The term 'dithering' refers to the way that dots of the different ink colours are combined, or interspersed, on a page to create the impression of an infinite variety of visible colours. This is similar, in many respects, to the way that a colour image is reproduced on a printing press.
Printing presses use a minimum of four ink colours to accurately reproduce 'full colour' images.
Just buy a replacement ink cartridge for the colour that's low and resume printing. It's rated 1,200 x 600 dpi. They can be very striking, with good colour saturation, and reportedly stand up well under repeated careful washings. Using the 2500 It took all of ten minutes to unpack and set up the 2500. The quick-start guide told us everything we needed to know to get the printer and its support software up and running.