Lighting up the night
Other than the exquisite architecture of Siena, Italy, one subconscious reason why people continously gush over its beauty is its lighting.
Notice that with incandescent lighting you can tell that the lady’s coat is actually red. The light fixtures (art pieces unto themselves) are just a few feet above eye level, better illuminating the street. Acting as spotlights, the textures of the buildings are richly illustrated.
Beauty has a price in Siena. The city uses high quality incandescent lighting rather than the yellow wash, but energy efficient high-sodium vapor lighting commonly used in parking lots. Hopefully technology will soon allow energy efficiency without turning this image completely yellow.
Although incandescent lighting spends somewhere around 80% of its energy on generating heat (rather than light), there are plenty of ways that municipalities can still improve on energy usage… without going all dreary.
One of the simplest ways is to actually point light _down_: there’s no reason for us to be lighting the underbellies of airliners… directional lighting allows us to make the most of the light we _do_ generate — giving municipalities the option of using lower wattages.
Another way is to artfully mix light sources: incandescents are energy hogs and have a short life (they’re engineered that way), but they throw a nice warm (read: yellow) glow; halogens also eat up energy, they’re a little more efficient than incandescent (and they last longer, too), they throw a truer light also; life expectancy for flourescents and sodium lights are extremely long, and they’re very efficient, but the light they throw is horribly skewed — green or purple. At any rate, with a mixture of lighting sources (all pointed _down_) it’s possible to lower costs while retaining quality of light.