The Electric Michelangelo by Sarah Hall

"There were five colours in the tattooing pallet, and a limited archive of symbols to cover the spectrum of life and death. Five colours to capture all the joys and sorrows of the world and hold them down against a piece of body. Red, brown, yellow, green, black. Five colours to say everything that could be said. And what Cy suddenly wanted, more than anything in the world right then, what he wanted was that missing blue, primary and resistant to the trade. Blue that was unstable and misbehaved when left in skin. Blue like the sea that had taken his father. Blue, for his mother's sake, and for the true colour of every bereaved and bloodless heart when it is collapsing"