In short, InC02 is a medium that has been designed to sense and respond to the presence of the greenhouse gas carbon dioxide (CO2) in the Earth’s atmosphere, and in doing this turns from a deep blue colour to being colourless. Any art made with it then is necessarily ephemeral, fleeting, and perhaps even futile, provided it is exposed to our planet’s atmosphere which contains both natural, and anthropogenic carbon dioxide. As in the video above, poetry written with InC02, drawings made with it, or textile designs printed with it, will all slowly disappear as it absorbs carbon dioxide from the air. Intriguingly, this greenhouse gas also becomes incorporated into any work made with the ink. Conversely, if any art made with it is stored in an atmosphere, or gas mix devoid of carbon dioxide, then under such conditions the works will be permanent.
The Carbon Dioxide Sensing Mechanism
The key component of InC02 is the pH indicator thymolphthalein which is blue at alkaline pH but turns colourless when exposed to acidic conditions. In a dilute solution of sodium hydroxide the pH indicator then will be a deep blue colour. However, as the carbon dioxide in the Earth’s atmosphere is absorbed into the ink it reacts with the water in the solution to form carbonic acid, which then in turn reacts with the sodium hydroxide form sodium carbonate. This reaction series lowers the pH of the solution, with the alcohol also acting as an acid, to turn the indicator into its colourless form
Instructions for making InC02 (at your own risk)
- Begin by adding 1g of thymolphthalein to 100 mL of ethanol and then stir to dissolve all of the powder.
- Next add 900 mL of water to the solution and stir. At this point the solution will become white and cloudy because the thymolphthalein indicator is not soluble in water.
- Finally, slowly add 10 mL of 3 molar sodium hydroxide to the solution to turn the liquid a dark blue.
The fading time can be prolonged by adding more sodium hydroxide. In addition, a red coloured version of InC02 disappearing ink can be made using phenolphthalein in place of thymolphthalein.