Actually, it so happens that I recently attended an event at a local community center in a room that got remarkable light, both natural daylight and well-placed overhead lights, and it got me thinking about lighting in tournament halls: How do you balance the need for good, clear illumination with the natural human desire to be in a place that feels, for lack of a better word, “alive”? Because a wash of green-tinged fluorescent tubing may meet the first criterion (usually, it exceeds it) but does nothing to serve the second; in fact, it generally undermines it.
The high-intensity geekery below will not only inform and enlighten you but also help you save on your electricity bills.
Illumination is measured in foot-candles (U.S. customary) or lux (metric). (Conversion is easy, since 1 fc is pretty close to 10 lux.) The minimum amount of illumination necessary for you to see what you’re doing is about 5 fc. Relaxed room lighting runs between 10 and 20 fc. Task work requires about 50 fc. (A typical classroom is overilluminated to 150 fc or more, which is a great waste: not only is the level of illumination much greater than necessary, but a lot of that light is shining on areas where nothing is going on. People like to sit in pools of light, not oceans of it.)
So how do you achieve the necessary amount of illumination for your task? Well, suppose you have an extra room in your house that you want to turn into a game room. The room is 10 feet by 12 feet – 120 square feet. You’ve placed your chess table in the middle of the room. You want relaxed lighting for the room, but you want task lighting for the chessboard. To achieve this, you have to obtain light bulbs that put out the necessary number of lumens, obtained by multiplying the desired illumination in foot-candles by the number of square feet, or the illumination in lux by the number of square meters. (Since 1 square meter is about 10 square feet, it balances out!) So, for your game room, you want 1,200 lumens of diffuse lighting for the room overall (giving the whole room 10 fc of lovely relaxed mood lighting), plus 450 lumens of spot lighting on your 3-by-3-foot chess table (giving it 50 fc so that you can see the pieces, the clock and the notation sheet with total clarity). Actually, you might want that spot light to be more than 450 lumens, especially if it’s a round bulb in a recessed fixture, because not all of the light will shine directly on your chessboard; some of it will be blocked or go off in other directions. Remember to estimate how much of the light from the bulb will be going where you want it to, and calculate accordingly.
As jjamesge1 mentioned previously, you also want to get lights with a color temperature of 2,700 K. These give off the warm, reddish light that we associate with incandescent bulbs and such other pleasant things as fire, as opposed to the icky greenish light that we associate with hospital emergency rooms, police stations and the SAT.
As it happens, there are lighting suppliers (I’m a fan of one called 1,000 Bulbs) that can tell you the color temperature and lumenage of every bulb they sell, so that you can get just the right lights to illuminate any space to exactly the level you want.
I haven’t experimented with LEDs yet, but as compact as they are, I can imagine that they’d serve nicely for recessed spot lighting. I have, however, used these calculations extensively to efficiently light my apartment with compact fluorescents – always matched in color to incandescent light, except in the bathroom, where I like a daylight-balanced 5100 K to wake me up in the morning.
With regard to shadows, if you don’t want them to be sharp, you need to place some kind of diffuser over your lights. In everyday parlance, these are known as lampshades. (The bumpy plastic sheets that go over fluorescent tube fixtures also serve this function.) Alternatively, you can bounce the light off another surface, like a white wall or the inside of a scoop-shaped fixture.
