contrast

How much the coverage of edges in dark colors is increased. At 1.0 the edges of dark colors look as heavy as when they are blended in sRGB, at 0.0 coverage is blended in linear light uncorrected, values above 1.0 increase the coverage further. The correction makes small type and thin lines in dark colors look closer to how browsers and other text renderers draw them. It fades out between dark and light colors, light colors are not corrected.

The default of 1.5 matches the weight of small dark type in browsers. It also makes strokes in dark colors look about 0.2 pixels heavier than SVG strokes in browsers, at 1.0 their widths match. Strokes drawn with the drawer are not corrected and look lighter at any setting.