The invention relates to the use of custom color inks in printing. According to various aspects of the invention, printing apparatus and processes are provided for dispensing a first primary color ink to a custom color chamber associated with a print head, dispensing a second primary color ink to the custom color chamber, mixing the first primary color ink and the second primary color ink to create a custom color, and printing the custom color ink from the custom color chamber with a print head. The invention also relates to using valves to select a printing ink from a number of available ink chambers.