Black Canon

Black Canon
Why are there two inkjet cartridges for my printer Canon black?

Will not print unless both are installed (along with all other color cartridges). My HP printer has only one black ink cartridge

I have the R1800 fee and two cartridges are needed because it is a matte black Black and Black is a picture. They work with different levels of darkness and the light that has to be in the printed image.

Canon CLI-221, CLI-521, CLI-821, CBI-321 Black and Colour – Refill Instructions