- Interpolate and choose colors in a perceptual color space (i.e. CIE L*C*h). [There are a handful of color ramp generators that interpolate in L*C*h, but selection is still in RGB or HSL (Magnaview and ArcGIS, for example.)]
- Automatically rotate through hue space, while simultaneously changing lightness and saturation. Allow clockwise and counter-clockwise rotation (red-yellow-green-blue or red-magenta-purple-blue).
- Also allow linear interpolation through 3-dimensional color space. Changing from blue to yellow without going through green, for instance.
- Maybe even support “weighting” of the transition: palettes that arc through color space, but aren’t a tight spiral or straight line.
- Generate continuous as well as discrete palettes, exported as an indexed color image or color table.
- Make the entire gamut of CIE L*C*h color space available.
- Allow “illegal” (out of gamut) colors, but indicate when these occur.
- Display the path of interpolation in a representation of the CIE L*C*h gamut. In 3D.
- Support multiple display color spaces: sRGB, Adobe RGB, CMYK, etc.
- Provide a preview image, or even allow upload of sample imagery.
- All built with modern web technologies that provide instantaneous feedback and an elegant user interface.
Spoiler alert: I’m working on this. Drop me a line if you’re interested in collaborating. Robert Simmon is a data visualizer and designer for NASA’s Earth Observatory. With 19 years of experience at NASA, he is an expert at creating clear and compelling imagery from satellite data. Robert focuses on producing visualizations that are elegant and easily understandable, while accurately presenting the underlying data. His imagery appears regularly in newspapers, web sites, and advertisements, and was featured on the login screen of the first Apple iPhone. Robert blogs about design and visualization on Elegant Figures and tries to keep track of the zeitgeist (and share the occasional dog photo) via his Twitter account, @rsimmon.