Figure 17.2.4.1 

Line-art molecular illustration. The figure on the left depicts the α-carbon backbone and molecular surface of the α subunit of haemoglobin (PDB code: 2hhb). Outlines define the shapes of the surfaces and tubes, and contour lines enhance their three-dimensionality. Hatch lines, normally used for shadows, are used here to darken the inside of the molecular surface. The figure on the right shows the interior of a human red blood cell (300 ų), showing all molecules except water. The picture is drawn with outlines defining each molecule. Shadows and depth cuing are used to enhance the three-dimensional character of the image. Contour lines are not used. From Goodsell & Olson (1992).