The contrasts change when dark to black paper instead of light paper is used as the base of the anaglyphs. These are called negative anaglyphs . The complementary colors then exchange their roles. During the examination of the color choices, it must be taken into consideration that the combination of the green color and the red filter as well as the red color and the green filter appear as dark as possible. Red color and a green filter work well together, green color and a red filter do not.
New problems arise with the printing of negative anaglyphs.
Red and green lines may not be printed but must be marked off against the surface, in about the same manner as in intarsias. For people wishing to draw negative anaglyphs, opaque colors, which allow nothing of the black undercoat to show through, are required. Because of their consistency, these covering colors cannot be manipulated with tubular quill pens. The old, adjustable, drawing pen is ideal. When working with the drawing pen, the colors must be diluted with water to a point where they just begin to drip.