What it does
CMasher provides scientific colour maps with tools for comparing, combining and sampling them under the free BSD 3-Clause licence. Python users can build plot-ready maps, and other applications can read the supplied RGB or HEX text tables.
Choose a map family from its overview, then preview the colour and grayscale versions. To avoid very dark or very light ends, select a sub-range; to colour separate lines, request a fixed number of evenly spaced colours and choose HEX output.
Sub-map extraction does not interpolate new colours. The guide recommends retaining at least 128 colours for a smooth continuous result, so a very narrow crop can produce visible steps. Separate maps can also be combined at specified positions rather than always splitting the range equally.
CMasher is free under the BSD 3-Clause licence. Standalone modules can carry a registered CMasher map into another Python project, while normalized RGB, 8-bit RGB and HEX tables support manual import into other software.
Strengths
- Grayscale previews expose changes in lightness.
- Sub-ranges and fixed-count samples serve different plotting needs.
- Text tables provide a route outside Python.
Watch out for
- Narrow sub-ranges can contain too few colours for a smooth result.
Best for
- Adapting scientific colour maps to a figure’s range
Sources
- CMasher overview and map families (Oct 27, 2026)
- CMasher usage, sub-maps and external formats (Oct 27, 2026)
- CMasher free access and BSD 3-Clause licence (Oct 27, 2026)