Your darkroom sink should be the proper size for your work and also be durable. It should drain the water totally from the sink. The sink should also have duckboards to keep your trays and tanks off of the sink's bottom. This will also let the water circulate under and around your solution tanks, keeping them at the proper and constant temperature. A darkroom sink should also have a mixing valve to control the temperature of the water in it. A good sink will also have a standpipe to hold the water in the sink at the proper depth, yet still enabling the water to flow out. Sinks are made of various materials such as fiberglass, plastic and stainless steel. They also come in various sizes. They usually range in price from about a few hundred dollars to over $1,000.