The existing specification for shading in a heat-map — note how little variation there is between the tints representing different values.
Fine-tuning the visualization
We’d recently updated our palette for data visualizations. These new specs included a gradient for each color that could be used in heat-maps or other range-based charts.
The problem was that we’d defined heat-map values as a range of 100% of a color to 10% of that same color. But if the color in question wasn’t terribly dark to begin with, the resulting tints were difficult to distinguish.
Put another way, the color space we’d defined was too narrow to allow users to easily differentiate relative values, diminishing the usefulness of the visualization.