Abstract: An improved color picture tube has a viewing screen, a shadow mask located adjacent to the screen, and an electron gun for generating and directing a plurality of electron beams through the mask to the screen. The mask has a rectangular periphery with two long sides and two short sides. A major axis passes through the center of said mask and parallels the long sides, and a minor axis passes through the center of the mask and parallels the short sides. The mask includes slit-shaped apertures aligned in columns that essentially parallel the minor axis. Adjacent apertures in each column are separated by tie bars in the mask. The beams are scanable over the screen in scanning lines that parallel the major axis. The improvement comprises the length of the apertures, measured in the direction of the minor axis, being approximately equal to a multiple of the center-to-center distance between adjacent scanning lines, measured in the direction of the minor axis.