Imatest also tests color accuracy, tone-scale linearity, image distortion, light falloff, and printing gamut. The falloff is approximated by the cos or "cosine fourth" law of illumination falloff. A simple generalization of metaballs is to apply the falloff curve to distance-from-lines or distance-from-surfaces. This helps overall lens performance, which is rated excellent on most respects except light falloff. The right image does use distance falloff. The left image doesn't use distance falloff. Much of the falloff in sales was attributable to customers being unable to arrange financing. Light falloff is also sensitive to f-stop. The studio was threatened with bankruptcy due to falloff in business because of the Depression. The falloff of the data at higher resolution is governed by Porod laws. The loss of the whip resulted in a falloff in Heffernan's Seanad voting attendance. The falloff in success of Hayes' last three years was not great.