Abstract: For use with a copier, apparatus is provided for selecting one of a plurality of sets for adjusting the contrast and density of copies. Each set defines a particular Din/Dout response curve. The apparatus includes a stored matrix of such sets with each set having at least three different values relating to: voltage Vo applied onto the photoconductor by the primary charger, copier exposure Eo, and bias voltage V.sub.B applied to a development station electrode. The operator designates a particular set and logic and control means, adjusts Vo, Eo, and V.sub.B in accordance with the designated set values, and causes the copier to have a particular Din/Dout response curve.