1 Introduction

Tol (2018) offers carefully chosen schemes, ready for each type of data, with colours that are:

• Distinct for all people, including colour-blind readers.
• Distinct from black and white.
• Distinct on screen and paper.
• Matching well together.

All the scales presented in Paul Tol’s technical note (issue 3.1, 2018-09-23) are implemented here, for use with base R graphics or ggplot2.

2 Qualitative data

According to Paul Tol’s technical note, the bright, contrast, vibrant and muted colour schemes are colour-blind safe.

The light colour scheme is reasonably distinct for both normal or colour-blind vision and is intended to fill labelled cells.

The pale and dark schemes are not very distinct in either normal or colour-blind vision and should be used as a text background or to highlight a cell in a table.

The qualitative colour schemes must be used as given (no interpolation): colours are picked up to the maximum number of supported values. Refer to the original document for details about the recommended uses (see references).

bright <- colour("bright")

plot_scheme(bright(7), colours = TRUE, names = TRUE, size = 0.9)

contrast <- colour("contrast")

plot_scheme(contrast(3), colours = TRUE, names = TRUE, size = 0.9)

vibrant <- colour("vibrant")

plot_scheme(vibrant(7), colours = TRUE, names = TRUE, size = 0.9)

muted <- colour("muted")

plot_scheme(muted(9), colours = TRUE, names = TRUE, size = 0.9)

light <- colour("light")

plot_scheme(light(9), colours = TRUE, names = TRUE, size = 0.9)

pale <- colour("pale")
dark <- colour("dark")

plot_scheme(pale(6), colours = TRUE, names = TRUE, size = 0.9)

plot_scheme(dark(6), colours = TRUE, names = TRUE, size = 0.9)

3 Diverging data

If more colours than defined are needed from a given scheme, the colour coordinates are linearly interpolated to provide a continuous version of the scheme.

sunset <- colour("sunset")

plot_scheme(sunset(9), colours = TRUE, size = 0.9)

BuRd <- colour("BuRd")

plot_scheme(BuRd(9), colours = TRUE, size = 0.9)

PRGn <- colour("PRGn")

plot_scheme(PRGn(9), colours = TRUE, size = 0.9)

4 Sequential data

If more colours than defined are needed from a given scheme, the colour coordinates are linearly interpolated to provide a continuous version of the scheme, with the exception of the discrete rainbow scheme (see below).

YlOrBr <- colour("YlOrBr")

plot_scheme(YlOrBr(9), colours = TRUE, size = 0.9)

iridescent <- colour("iridescent")

plot_scheme(iridescent(23), colours = TRUE, size = 0.5)

discrete_rainbow <- colour("discrete rainbow")
smooth_rainbow <- colour("smooth rainbow")

plot_scheme(discrete_rainbow(14), colours = TRUE, size = 0.7)

5 Diagnostic maps

5.1 Qualitative colour schemes

Diagnostic maps for the bright, vibrant, muted and light (from top to bottom) qualitative colour schemes.

5.2 Diverging schemes

Diagnostic maps for the sunset, BuRd and PRGn (from top to bottom) diverging colour schemes.

5.3 Sequential schemes

Diagnostic maps for the YlOrBr, iridescent, discrete rainbow and smooth rainbow (from top to bottom) sequential colour schemes.