k3d/share/shaders/k3d_graphic_lines.sl:16:        float contrast_highlight=1.0;
k3d/share/shaders/k3d_graphic_lines.sl:39:        float contrast_paint=1.0;
k3d/share/shaders/k3d_graphic_lines.sl:62:        float contrast_ink=1.0;
k3d/share/shaders/k3d_graphic_lines.sl:137:	illumination_highlight=(illumination_highlight*contrast_highlight)+(1.0-contrast_highlight)/2.0+(brightness_highlight-1.0)+n_highlight*randomness_highlight;
k3d/share/shaders/k3d_graphic_lines.sl:211:	illumination_paint=(illumination_paint*contrast_paint)+(1.0-contrast_paint)/2.0+(brightness_paint-1.0)+n_paint*randomness_paint;
k3d/share/shaders/k3d_graphic_lines.sl:283:	illumination_ink=(illumination_ink*contrast_ink)+(1.0-contrast_ink)/2.0+(brightness_ink-1.0)+n_ink*randomness_ink;
k3d/share/shaders/k3d_srfdeformation.sl:15:   additional contrast and color controls are left as an exersize
k3d/share/shaders/k3d_woodcut.sl:5:float contrast=0.3; 
k3d/share/shaders/k3d_woodcut.sl:56:illumination = (illumination * contrast) + (1.0 - contrast)/2.0 + 
