Some of the more sophisticated HP, Lexmark and Canon printers take not only black and colour ink cartridges, but also a photo cartridge. The use of photo cartridges is easily misunderstood, so we thought you might like an explanation. Commonly used photo cartridges are the HP348, HP58, Lexmark 31 and Lexmark 90. The Canon CL-52 is also a photo cartridge and has its own specific port in the printers it fits. A photo cartridge contains three colours – black, light cyan, and light magenta – about one third of each. They work alongside the usual tri-colour cartridge (cyan, magenta and yellow) to provide the very best colour definition possible. The photo cartridge fits into the black port on the printer. When printing NON-photo matter, it makes sense to use a BLACK only cartridge next to the colour one, because colour definition is less critical, and it works out much cheaper. If you use up all the black ink in a photo cartridge by printing emails, letters etc, you’ll end up throwing away the remaining 2/3rds of the ink (the light cyan and light magenta). When not in use the photo cartridge can be stored near the printer in the clip it’s provided with. When printing photos – install the photo cartridge and store the black cartridge in the clip. Hope that’s clear – you can always email us for advice if it’s still a bit hazy!