Different cities have different economies, with different surpluses and deficits of materials.
For instance, Curow and Ahmerrad always have cheap iron, so Ironworks built in those cities are quite profitable for the price. Shariz is a great place for a linen weavery. And so on.
However, many cities don't have any particularly good surpluses/deficits. In those cases, building a dyeworks is your best bet. Reyvadin is one of those cities.
But as stormcricket and Blackfish have pointed out, a dyeworks will reliably produce about 500-600 denars of profit a week, without much variation from city to city. Except the Rhodok towns; velvet is cheap in the Kingdom of Rhodoks for some reason, so don't build dyeworks there. Also, Bariyye appears to be the only city that has cheap Dyes, so that will be the only place where you can reliably get 600+ denar profit from your dyeworks.