Online color apps at

The web page has been relaunched, hosting three online color apps based on the HCL (Hue-Chroma-Luminance) color model: a palette constructor, a color vision deficiency emulator, and a color picker.

HCL wizard: Somewhere over the rainbow

The web page had originally been started to accompany the manuscript: “Somewhere over the Rainbow: How to Make Effective Use of Colors in Meteorological Visualizations” by Stauffer et al. (2015, Bulletin of the American Meteorological Society) to facilitate the adoption of color palettes using the HCL (Hue-Chroma-Luminance) color model. It was realized using the R package colorspace in combination with shiny.

After the major update of the colorspace package the has also just been relaunched, now hosting all three shiny color apps from the package:

HCL wizard color apps

Palette creator

This app allows to design new palettes interactively: qualitative palettes, sequential palettes with single or multiple hues, and diverging palettes (composed from two single-hue sequential palettes). The underlying HCL coordinates can be modified, starting out from a wide range of pre-defined palettes. The resulting palette can be assessed in various kinds of displays and exported in different formats.

HCL wizard palette creator

Color vision deficiency emulator

This app allows to assess how well the colors in an uploaded graphics file (png/jpg/jpeg) work for viewers with color vision deficiencies. Different kinds of color blindness can be emulated: deuteranope (red deficient), protanope (green deficient), tritanope (blue deficient), monochrome (grayscale).

Color vision deficiency emulator

Color picker

In addition to the palette creator app described above, this app provides a more traditional color picker. Sets of individual colors can be selected (and exported) by navigating different views of the HCL color space.

HCL color picker