There's a lot of carbon in automobile exhaust. Carbon is also used as a pigment in black ink. The guys at Singapore-based Graviky Labs have combined the one with the other, by harvesting carbon from vehicles' tailpipes to make their own eco-friendly AirInk. It's currently the subject of a Kickstarter campaign.
Air-Ink started out as a 2013 experiment at the MIT Media Lab, in which candle soot was being captured and repurposed as printer toner. It's evolved in the years since. Here's how it works now …
First, a cylindrical filtration device known as the KAALINK is retrofitted to a car's tailpipe, where it collects a claimed 95 percent of particulates from the exhaust. That soot is subsequently processed to remove heavy metals and carcinogens. The resulting carbon-rich powder is reportedly safe to handle, and is used as black pigment in the group's ink.
In its current form, the process isn't particularly conducive to large-scale ink production. Graviky Labs is hoping to change that, though, using proceeds from the Kickstarter campaign.
Pledge levels start at US$25, which will get you a 2mm-tip AirInk marker … assuming things go according to plan. As a side note, 45 minutes worth of emissions are reportedly enough to produce one fluid ounce of ink, which is enough to fill one of the pens.
Complete pen sets and bottled ink for silkscreening are available for higher pledges.