Painting a house

Most paintable locations (ships, shoppes, stalls) have holds, and can have paint delivered to them for painting.

Houses are the exception. You cannot use your own paint to paint a house; you must purchase the paint "dockside".

To do this, the paint that you want must be currently being sold on the island, for immediate pickup. Being able to place an order at the apothecary is not sufficient. Having an order of paint ready to deliver is not sufficient. It must currently be being sold by a shoppe, typically apothecaries, furnishers, and shipyards. Palaces will sometimes sell paint dockside as well.

In short: You need a paintbrush, and cash on hand; having paint itself will not help. You will be able to paint your house by being in it and clicking on the paintbrush you own.