Aquatint is an intaglio printmaking technique, a variety of etching widely used by printmakers to achieve a broad range of tonal values. Like etching, aquatint uses the application of acid to make the marks in the metal plate but this technique is used to create tonal areas and texture in a print. Instead of receiving single black lines through etching, aquatint uses powdered rosin which is acid resistant in the ground to create a tonal effect, imitating watercolor painting.
     In this process the metal plate is slightly covered with very thin acid-resin base /etching ground - asphalt grain or rosin powder /, and then heated so the resin melts and clings. The more fine dust are, the more fine tone is received. Contemporary printmakers often use spraypaint instead of a powder. If the plate is covered with powder, the resin melts forming a fine and even coat. Produced grainy texture like grit, which print tones of gray or color nuances depending on the color of ink used. The tonal variation is controlled by the level of acid exposure over large areas, and thus the image is shaped by large sections at a time.
     Then begins immersing the plate in the nitric acid solution. An infinite number of tones are achieved by exposing various parts of the plate to acid baths of different strengths for different periods of time. But first the artist will then etch an outline of any aspects of the drawing he wishes to establish with line; this provides the basis and guide for his later tone work. He have to applied (at the very start, before any biting occurs) an acid-resistant "stop out" (also called an asphaltum or hard ground) if he intends to keep any areas totally white and free of ink, such as highlights. The first etch should be for a short period of time (30 seconds to 1 minute, with a wide variation depending on how light the lightest tones are meant to be). After removing, shall be cover other areas to be tinted in light gray and the form returned to the bath this time for 10-15 seconds, etc. Progressively stopping out (protecting from acid) any areas that have achieved the designed tonality. This procedure is repeated until it reaches a few minutes, which will print in black and tight. More than thirty minutes should produce a very dark area. The aim is to graduate graphic spots. Usually make four or five stages but sometimes much more. These tones, combined with the limited line elements, give aquatints a distinctive, watery look. Also, aquatints, like mezzotints, provide ease in creating large areas of tone.
     Printing is as in etching. From plate can be removed about 10 quality prints. The technique is rarely used alone, in most cases is in addition to etching. This is a demanding and difficult technique takes years to learn and improve, but the end result is a graphic impression of light and color as transparent quality colors as an aquarelle.
     Aquatint is rarely employed by itself, but rather in combination with other intaglio methods.
     In the 17th century a number of attempts were made at producing what later became known as aquatint prints. None of the efforts was successful, however, until 1768, when the French printmaker Jean-Baptiste Le Prince discovered that granulated resin gave satisfactory results. Aquatint became the most popular method of producing toned prints in the late 18th century, especially among illustrators. Its textural subtleties, however, remained largely unexplored by well-known artists except for Francisco de Goya. Most of his prints are aquatints, and he is considered the greatest master of the technique.
     After Goya.s death, aquatint was largely ignored until Edgar Degas, Camille Pissarro, and Mary Cassatt together began to experiment with it. Sugar aquatint, sometimes called sugar lift, was another method that came into widespread use in the 20th century owing to the work of artists such as Pablo Picasso and Georges Rouault. Many contemporary printmakers also use pressurized plastic sprays in place of resin.