The palette
Red brick for the enormous Victorian belt, and Yorkshire stone, blond and lighter, for the small centre and the civic buildings. A map has one ink for all its buildings and cannot split them by district, so lay the blond stone on the ground of the sheet and the brick on the buildings, and the two stay distinct rather than blending into one brown. The Aire corridor wants a dark horizontal, water and iron together, because it is the line that holds the page up. If you mark the ring road, let it read as a cut rather than an avenue. Keep the green at the edges: this is the opposite of a city of parks, and moving green inwards would be a lie.