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Methods & data.

How the collection is put together, and the rules every view follows. Each visualization also has a “How to read this” panel beside its title that explains what it shows.

Where the works come from

Artwork records and images come from the open-access collections of these museums and archives, along with Wikidata:

  • National Gallery of Art
  • Smithsonian American Art Museum and other Smithsonian collections
  • Cleveland Museum of Art
  • Art Institute of Chicago
  • The Metropolitan Museum of Art
  • Minneapolis Institute of Art
  • Victoria and Albert Museum
  • Cooper Hewitt, Smithsonian Design Museum
  • Tate
  • Princeton University Art Museum
  • Library of Congress
  • The Dorothy and Herbert Vogel Collection: Fifty Works for Fifty States

Titles, dates, media and credit lines are the museums' own. Biographical facts such as birth and death years and nationality come from Wikidata and museum records. The collection reflects what these institutions hold and publish online, which leans toward European and American art.

How colors are measured

For each artwork image, the pixels are grouped into its eight main colors, ordered by how much of the picture each one covers. When a photograph shows a backdrop around an oval or shaped work, the backdrop is left out.

The colors are what the photograph shows. Lighting, the camera, yellowed varnish and the aging of the paint all play a part, so an old painting can read warmer or darker than it looked when it was new.

Pigment Weather and Career Ribbons use only flat works: paintings, drawings, prints, textiles and photographs. Photographs of sculpture and objects include walls, pedestals, sky and tabletops, so their colors aren't the work's own. The Palettes view currently includes every work with an image, and its panel says so.

Rules every view follows
Removals stay removed
Works taken down at someone’s request, and works found to be misattributed, go on a blocklist. They never come back, even when a museum’s data is imported again.
Impossible dates are dropped
A painting or drawing dated after its artist died, or before they turned 8, is left out of timelines. This is usually a data mix-up, such as a birth year stored as the date the work was made. Prints, casts and photographs can be made after an artist’s death, so they are kept.
Vague dates stay out of timelines
When a museum can only date a work to a span of more than 25 years, it isn’t placed on a timeline.
Duplicates are merged
One artist stored as two records is merged into one, and a work imported twice (from a museum and from Wikidata) appears once.
Artist records are checked
Birth and death years, gender and identity are compared against Wikidata. Disagreements are corrected only with a source.
Artist and movement texts

Profiles are written by Claude Opus 5.5 (Anthropic) from each artist's Wikipedia article and the museum records of their works, then stored, so every visitor reads the same text. Samples are fact-checked claim by claim against sources. Each profile lists what it was written from and has a “Report an inaccuracy” link underneath. More on this on the About page.

Found a mistake?

Use the bug reporter in the lower right of any page. You can highlight the exact thing that's wrong. Every report is read, and corrections are made with a source.