The palette
Three rivers and a canal: the water ink is the principal colour here, and it has to stay legible down to a two pixel thread. Take it deep, with no transparency, and be wary of soft blues, which will make the great river handsome and erase the canal, which is to say the subject. Green counts too, but differently: the wooded masses in the north-west and the farm in the south are the two breaths in this sheet, and too pale a tone would hand them back to the built fabric. The rest can stay light.