What it does
Colorcet supplies continuous colour maps and categorical sets for Python plots, free under CC BY 4.0 with attribution. It exposes the same maps as RGB values, HEX lists and Matplotlib objects, with documentation explaining which family suits each data role.
Import colorcet and select a named palette such as fire. Bokeh-style HEX palettes are ordinary lists, so they can be sliced or reversed. Matplotlib maps are available as objects and registered names with a cet_ prefix; reversed variants are supplied too.
The plotting helpers display one map or a group of swatches, but require HoloViews. The underlying colour lists do not depend on that preview workflow. Continuous maps aim at perceptually regular changes, while categorical sets aim to separate groups.
Colorcet is free under CC BY 4.0, including commercial use with the licence’s attribution conditions. Choose from the documented families carefully: the project explicitly says that not every map is suitable for monochrome reproduction or colour-vision deficiencies.
Strengths
- One map is available in several plotting-friendly representations.
- Lists can be subsetted without a separate export step.
- The guide distinguishes continuous and categorical uses.
Watch out for
- The supplied swatch plotting helpers require HoloViews.
- Not every map is colour-blind-safe or suitable for monochrome output.
Best for
- Using documented colour maps across Python plotting libraries
Sources
- Colorcet introduction and map limitations (Oct 27, 2026)
- Colorcet map access and plotting guide (Oct 27, 2026)
- Colorcet open-source access (Oct 27, 2026)
- Colorcet CC BY 4.0 licence (Oct 27, 2026)