I found this forever ago via something or another (Design Boom most likely) but never posted it. It’s a beautiful, creative way to mark the flow of time through a physical manifestation. It is also a pretty awesome example of exacting craftsmen ship, because trying to figure out the correct level of viscosity for this to work properly would have driven me mad. From the creators website Oscar Diaz Studio (http://www.oscar-diaz.net/?p=1):
Calendar using the capillary action of the ink on the paper.
“Ink Calendar” make use the timed pace of the ink spreading on the paper to indicate time.
The ink is absorbed slowly, and the numbers in the calendar are “printed” daily. One a day, they are filled with ink until the end of the month. A calendar self-updated, which enhances the perception of time passing and not only signaling it.
The ink colors are based on a spectrum, which relate to a “color temperature scale”, each month having a color related to our perception of the weather on that month. The colors range from dark blue in December to, three shades of green in spring or oranges, red in the summer.
The scale for measuring the “color temperature” that I have used is a standard called ‘D65’ and corresponds roughly to a midday sun in Western / Northern Europe.
The “Ink Calendar” was developed for “Gradual “, an exhibition featuring works, which were evolving during the exhibition time at the London Design Festival 2007
I wish it wasn’t just a prototype, because this marketed would be something I would love to buy.