Which finish would be most appropriate for a kitchen cabinet subject to high humidity?

Polyurethane is the most appropriate finish for kitchen cabinets that are subject to high humidity due to its excellent water resistance and durability. This finish forms a hard, protective layer that effectively repels moisture, making it ideal for areas like kitchens where humidity levels can fluctuate due to cooking and cleaning activities. Polyurethane is also resistant to wear and tear, which means it can withstand the everyday use and potential spills that might occur in a kitchen setting.

Oil-based paint, while durable, does not offer the same level of moisture resistance as polyurethane. It may also take longer to dry and can be more prone to yellowing over time. Lacquer is not the best choice in humid environments as it is less moisture-resistant and can be damaged more easily by water, affecting both the appearance and integrity of the finish. Varnish can offer some protection, but it typically does not provide the same hardness and water resistance as polyurethane, making it less suited for high-humidity areas compared to polyurethane finishes.