English painter and printmaker J.M.W. Turner, who was active in the late 18th and early 19th centuries, was astonishingly prolific. On his death, he left over 550 oil paintings, 2,000 watercolors and more than 30,000 works on paper.

Many of the latter are pages from his sketchbooks, and many of those are in the collection of the Tate Britain as part of the extraordinary Turner Bequest, which brought the museum’s holding of Turner’s works to over 37,000.

The Tate has put a number of these online, in a special section of their website: J.M.W. Turner: Sketchbooks, Drawings, Watercolours.

The resource is divided into 5 chronologically arranged sections from different points in the artist’s career, and within that, the works are arranged in subsections by location or other theme. Exploring is a matter of drilling down through the categories to subcategories.

Eventually, you will come to pages in which an individual sketchbook or thematic group of works is available in a slideshow. In the initial window of that slideshow there are usually two tabs, allowing you to choose between “Entry” (the slideshow) and “At a glance” or “Artworks”. Choosing the latter will open up thumbnails of the images arrayed directly on the page, making them much easier to browse.

For example, in the section “1819-29 Italy and After“, there is a subsection for “Rivers of England c. 1822-4” and a subsequent subsection for “‘Rivers of England’ Watercolours“.

From there you can click on a thumbnail to go to the detail page for an artwork, and there click on the image for an enlarged view. Most of the images are available in a nicely large size.

A number of the sections contain sketchbook pages that are so light or barely notated that they may be of less interest, but if you patiently dig around, you will be rewarded with many extraordinarily accomplished works in watercolor and gouache.

The sections for “Loose Studies of Paris and the Seine” and “Meuse-Moselle Gouache and Watercolour” (among others) are particularly of interest to those who are interested in Turner’s masterful handling of gouache as a sketching medium.

This project is so extensive, so wonderful and so engrossing, that I will issue a Time Sink Warning.