Using SVG filters to turn a grayscale image into a multi-toned image with pure whites and blacks but colored mid-tones. Not sure if there is a name for this in traditional graphic printing.
If you un-comment the section of CSS, the color becomes a hover effect.
See the Fun with Color Filters collection for more.
Forked from Amelia Bellamy-Royds's Pen CSS Filters Gray -> Color.