A series of N-cycloalkylcarboxamide derivatives of N-benzyl benzenesulfonamides of Formula I are described. The memory array circuitry may contain circuitry to switch a power supply line of a column of memory elements in the array to an appropriate power supply voltage during reading and writing operations. A linear equation is used to relate the spectral reflectance difference to solid ink density or ink layer thickness differences for ink regulation utilizing an on-line empirically established correction matrix such that the spectral reflectance difference is minimized.