A method of stretching films in which all or a portion of the width of the
film is cooled during or just after stretching so as to improve the
uniformity of the film. The includes stretching a polymeric film in a
tenter that grasps the film with a plurality of clips along the opposing
edges of the film and propels the clips to thereby stretch the film. The
tenter includes driven clips and idler clips, with at least one idler
clip between respective pairs of driven clips. The cooling is done so as
to improve the uniformity of the clip spacing relative to the spacing
obtained at otherwise identical process conditions without such cooling.