Watercolor's defining characteristic — that the white of the paper is the lightest value in the painting, because the medium is transparent rather than opaque — determines everything about how it looks and what it can do. Unlike oil or acrylic, you cannot paint light over dark in traditional watercolor. The light areas must be planned and preserved from the beginning. The medium rewards planning and punishes revision.

The practical appeal was portability. Oil painting requires elaborate equipment; watercolor required a small box of pans, a brush, and a pad of paper. British landscape painters of the late 18th and early 19th centuries — Thomas Girtin and J.M.W. Turner most prominently — developed watercolor into a serious fine art medium, and its portability let them paint outdoors, directly observing the light and atmosphere they wanted to capture.

The impressionist transparency of the medium — the way colors mix optically on the wet surface, the soft blooms where wet paint meets wet paper, the hard edges of dried washes — became an aesthetic in its own right, signaling a specific relationship between artist and subject: observational, sensitive, time-aware.

J.M.W. Turner became a full member of the Royal Academy in 1802 — the second-youngest artist in the institution's history to reach that rank, though he is often wrongly called the youngest. For his debut as a full Academician he prepared two Dutch-style seascapes, Fishermen Upon a Lee-Shore in Squally Weather and Ships Bearing Up for Anchorage. Source ↗

The Winsor & Newton company was founded in London in 1832 by William Winsor and Henry Newton. In 1835 it developed a watercolor containing glycerine, and in 1842 William Winsor patented a screw cap for collapsible metal tubes, after which the firm began selling watercolor in tubes. Source ↗