A printer system, comprising, for each of one or more ink color groups: a first primary ink tank holding a dark-colored ink; a second primary ink tank holding a light-colored ink; a first selector valve configured to change a state according to a print mode of the system; a first secondary ink tank connected to the first primary ink tank via the first selector valve, the first secondary ink tank configured to store the dark-colored ink and to provide the dark-colored ink to a first set of print heads; a second secondary ink tank connected to the first and second primary ink tanks (201, 203) via the first selector valve, the second secondary ink tank configured to store either the dark-colored ink or the light-colored ink and to provide the dark-colored ink or the light-colored ink to a second set of print heads according to the state of the first selector valve;a second selector valve connected to the first primary ink tank configured to return the dark-colored ink from the first or the second set of print heads (211, 213) to the first primary ink tank; a third selector valve connected to the second selector valve and the second primary ink tank configured to either return the light-colored ink from the second set of print heads to the second primary ink tank or to direct the dark-colored ink to the second selector valve; and a control device configured to: initiate, based on the print mode of the system, a changeover process for switching an ink stored in the second secondary ink tank; and operate the third selector valve to perform the changeover process, wherein the changeover process comprises: drawing an existing ink from the second secondary ink tank to a corresponding primary tank (201, 203); purging the existing ink from the second secondary ink tank; filling the second secondary ink tank with a different ink; flushing the second secondary ink tank and corresponding ink lines using the different ink; and circulating the second secondary ink tank and the corresponding ink lines to remove remaining air. a first primary ink tank holding a dark-colored ink; a second primary ink tank holding a light-colored ink; a first selector valve configured to change a state according to a print mode of the system; a first secondary ink tank connected to the first primary ink tank via the first selector valve, the first secondary ink tank configured to store the dark-colored ink and to provide the dark-colored ink to a first set of print heads; a second secondary ink tank connected to the first and second primary ink tanks (201, 203) via the first selector valve, the second secondary ink tank configured to store either the dark-colored ink or the light-colored ink and to provide the dark-colored ink or the light-colored ink to a second set of print heads according to the state of the first selector valve;a second selector valve connected to the first primary ink tank configured to return the dark-colored ink from the first or the second set of print heads (211, 213) to the first primary ink tank; a third selector valve connected to the second selector valve and the second primary ink tank configured to either return the light-colored ink from the second set of print heads to the second primary ink tank or to direct the dark-colored ink to the second selector valve; and a control device configured to: initiate, based on the print mode of the system, a changeover process for switching an ink stored in the second secondary ink tank; and operate the third selector valve to perform the changeover process, wherein the changeover process comprises: drawing an existing ink from the second secondary ink tank to a corresponding primary tank (201, 203); purging the existing ink from the second secondary ink tank; filling the second secondary ink tank with a different ink; flushing the second secondary ink tank and corresponding ink lines using the different ink; and circulating the second secondary ink tank and the corresponding ink lines to remove remaining air. initiate, based on the print mode of the system, a changeover process for switching an ink stored in the second secondary ink tank; and operate the third selector valve to perform the changeover process, wherein the changeover process comprises: drawing an existing ink from the second secondary ink tank to a corresponding primary tank (201, 203); purging the existing ink from the second secondary ink tank; filling the second secondary ink tank with a different ink; flushing the second secondary ink tank and corresponding ink lines using the different ink; and circulating the second secondary ink tank and the corresponding ink lines to remove remaining air. drawing an existing ink from the second secondary ink tank to a corresponding primary tank (201, 203); purging the existing ink from the second secondary ink tank; filling the second secondary ink tank with a different ink; flushing the second secondary ink tank and corresponding ink lines using the different ink; and circulating the second secondary ink tank and the corresponding ink lines to remove remaining air.