Aquatint is an intaglio printmaking technique and a variant of etching (indirect intaglio) in which the metal plate is prepared through corrosion. A porous plate surface is produced by sprinkling powdered pine resin or asphalt on the surface of the plate, heating the plate to fix the powder and corroding the metal. Unlike lines produced by etched plates, a plate prepared this way enables expressions of areas with varying tones like that of watercolors.

Pine resin is commonly used for this technique. First, the resin is ground into fine powder in a mortar and wrapped in a piece of cloth such as a gauze or a hand towel. Next, the solvent cleans off the plate and the resin powder is sprinkled over the plate by shaking the cloth up and down. This has to be done in an enclosed space where there is no breeze. The air conditioner should be turned off if it is to be done indoors. This is to prevent the powder from scattering. Once the plate has been sprinkled evenly with pine resin, heat the plate carefully over a gas stove from the reverse side to melt and fix the resin on the plate. The reticulated pattern of pine resin produced on the surface will act as an anticorrosive. Conversely, the exposed metal sections between the resin particles will be corroded in grains. These depressions will hold ink and produce areas of varying tones. The plate must then be cooled before corroding it to the desired tone. After that, alcohol is used to remove the pine resin.

The most important factors in aquatint are the amount of pine resin sprinkled and the degree to which the plate is heated. Sprinkling too much resin and covering the entire plate would prevent adequate corrosion. The same would be true if the plate was overheated. On the other hand, if it is not heated sufficiently, the pine resin will peel off during corrosion and the entire plate will be corroded evenly. Therefore, these steps must be performed carefully. A device called an aquatint box is sometimes used for sprinkling pine resin. This is used by placing the plate in the sealed box and then using the blower or fan attached to the bottom of the box, or compressed air, to throw up a dust of resin powder to spread it evenly over the plate surface.