Fig. 10

Trade routes drawn in ‘Area 29’ of the Selden map in Fig. 1 showing that they were drawn before the colorants were applied: a colour image, b 400 nm near UV image and c 880 nm near infrared image showing the black carbon based drawings and the copper green paint show up in dark grey; d 600 nm image subtracted from 880 nm image showing both the carbon black drawings (the cracks in the map show up as dark grey) and the indigo drawings (shows up as white though some parts of the brown to the right also show up as light grey). Note that the trade routes are usually accompanied by Chinese characters that indicate their compass bearing