By Charles Linn

When you think of lamps and light fixtures, wood probably isn't the first material that comes to mind. Yet wood is a natural choice for the job. It's strong and plastic enough to be worked into almost any shape. What's more, wood has a character all its own. A light source plays up the form, color and texture of wood in subtle and wonderful ways. A wooden light fixture can add a tremendous amount of cozy warmth to a room.

As versatile as it is. wood isn't suited to every type of lighting fixture design. There's no reason to make wood imitate what metal can do better. I wouldn't bother making a swing-arm desk lamp out of wood, for example. It would require large sticks of wood to equal the strength possible with thin metal tubing. When you design, I suggest you capitalize on the qualities of wood, using light to dramatize its color and textural patterns.

In this article, I'll cover the basics of designing and building wooden lights. I'll give you some guidelines for making them safe, and I'll outline the basics on lamp hardware and wiring. There isn't room here to give you a crash course on electrical wiring. If you aren't familiar with basic wiring practices, study up on the subject before you attempt any wiring. An improperly wired lamp can be dangerous.

Designing with Light

One of the first things you'll want to think about when designing a lamp is what you want the lamp to light. Light can create different moods depending on the way it's used. Consider whether the light fixture you design should distribute the light over a wide area or focus it in one place (see Fig. 1).

Task Lighting —Task lighting fixtures are used to direct light onto an activity that requires a high degree of visual acuity. The more visually demanding the task, the more light is required. The swing-arm desk lamp I mentioned above is a good example of a

task light. Task lighting requires that the light be concentrated onto a small area, so a reflector is usually used to control the light. A room that uses only task lights for illumination may appear like a cave with a few candles burning in it.

Ambient Lighting —Ambient light fixtures are intended to spread a minimum level of light more or less uniformly throughout a room. This light is used to balance the bright, concentrated light provided by task lighting. Ambient lighting is often provided by down-lights, table and floor lamps, and other fixtures that use diffusers to spread light out over a wide area.

Glare—Failure to balance brightnesses in a room can cause a condition known as glare. Glare occurs when there is a source of light within the field of view-that is much brighter than the rest of the light within view. Our eyes are unable to reconcile these great differences in brightness. The momentary blindness a driver experiences from the bright headlights of an oncoming car is an extreme example of this phenomenon. A bare lightbulb in a room can be a source of glare.

Glare is sometimes an indication of wasted light, and wasted light means wasted energy. Sometimes the same amount of energy used to power one bright spotlight, which dumps most of its light in one place, could light an entire room, if all the light coming out of that lamp were distributed evenly across the room.

Controlling Light—There are several ways to control light (see Fig 2). One is to provide a diffuser. A diffuser intercepts the light rays emanating from a light-

An Expert Sheds Light on Design and Construction

bulb and spreads them out over a wide area, diminishing the brightness and scattering the beams in many different directions. Fabric lampshades, translucent globes, sheets or disks, stained glass, fiber panels, even a thin, translucent piece of wood can be used as diffusers.

Another way to control light is to use a reflector. The reflector bounces the light of a lamp according to this simple law of physics: the angle at which a light ray strikes a surface equals the angle at which it will reflect. This principle can be used to design reflectors that concentrate light into a tight beam or spread it out over a wide area. The most efficient reflectors have a shiny surface. Polished copper or brass sheet will do, and work nicely with wood. If a shiny surface isn't appropriate, a light-colored surface will work, although a light-colored surface used as a reflector also causes some diffusion.

Some lightbulbs have built-in reflectors. PAR lamps, and their lighter-weight cousins R lamps, have built-in parabolic-shaped silvered surfaces that concentrate the light into a beam. Light from bulbs with built-in reflectors is concentrated, and tends to be harsher and cast more distinct shadows than light which is diffused either by penetrating a diffuser or bouncing off a light-colored surface.

Another method of controlling light is through the use of prisms. These transparent, triangular shapes reflect light at some angles and refract it at others. Many light fixtures use prismatic sheet (clear plastic formed into hundreds of rows of tiny pyramids) to dis-

rcmwisoN

Hanging lamp (top) on leather straps and wal lantern (right) are reproductions of turn-of-the-century lamps by CaBfomia architects Greene & Greene. Stained glass has iridized coating for a pear I-escent look when lamps are off. Dennis firm, Arboies, CO.

Hanging lamp (top) on leather straps and wal lantern (right) are reproductions of turn-of-the-century lamps by CaBfomia architects Greene & Greene. Stained glass has iridized coating for a pear I-escent look when lamps are off. Dennis firm, Arboies, CO.

Hanging lamp (left) in ash. Three hollow forms, turned from green wood, are thin enough to be translucent Light shining through the wood high-lights tool textures and variations in the grain. Darid EMsworth, Quakertown, PA.

Hanging lamp (left) in ash. Three hollow forms, turned from green wood, are thin enough to be translucent Light shining through the wood high-lights tool textures and variations in the grain. Darid EMsworth, Quakertown, PA.

Swing-arm wal lamp (far left) in walnut with paper and wood shade. Arm pivots on do*fl in

wo oracKexs. unoveaiwe ring that grips cord on arm sSdes to raise and lower arm. Table lamp (right) has scarf-Joined mahogany hoops around walnut legs with paper shade. John Fishefp Sotcbury, PA.

tribute light over a large area. Some glass globes have triangular-shaped ribs that focus light into beams while creating an attractive luminous pattern on the glass reflector itself. Holophane Lighting Company (214 Oakwood Ave., Newark, OH 43055) manufactures prismatic glass shades and globes in hundreds of different styles.

Working Up a Design

In its simplest form, a light fixture is nothing more than furniture for holding up a light socket, lamp, and either a d iff user or reflector. It's almost an entirely separate system from the wiring and electrical parts.

Just about all you've got to do to design a light is decide how to connect the socket, diffusers or shades to the wooden unit, and how you'll wire it safely.

When I design a light, I start off thinking about what I want my fixture to do. If I want it to provide ambient light in the room, I need to diffuse a light source, so I might design an uplight —a tall floor lamp, with a glass, prismatic reflector which would be aimed toward the ceiling. Ambient light could also be provided by a lampshade or diffusing globe. If I wanted to put task light on a desk. I might use some sort of shade to cover a small-wattage R lamp. There are an endless number of possibilities. Many ideas will suggest themselves to you when you begin to peruse the endless variety of lighting hardware available at your local lighting store (see sidebar).

For a beginner, the way a reflector or diffuser affects light may be the most difficult part of visualizing a light fixture design. I suggest that you try holding different types of reflectors or diffusers over different types of bare lightbulbs, just to see what happens, before deciding on a particular combination of the two.

A nice glass diffuser or reflector can make an excellent starting point for a wooden light fixture design. Many different types of diffusers and glass reflectors can be found at lighting stores or home improvement centers. I like to look for unusual glass shades at architectural salvage shops. Some can be had for next to nothing, some are quite pricey.

I like to start designing with rough pencil sketches. Sketching allows me to get a lot of design ideas on paper in a hurry. I've found that when I draft with a T-square, triangle, and a ruler, the hard precision of the lines—and the time required—somehow signal a kind of finality to what I've drawn. They make me less liable to experiment with the forms. With sketching, I feel free to play around and try lots of different ideas. And I always draw front, top and side elevations at the same time, so there are no suprises when I start building the fixture.

I sketch with a soft lead pencil on tracing vellum, a translucent paper used by architects, which has a light blue '/¿-in. grid printed on it. The translucent nature of the paper allows me to overlay my drawings with fresh sheets, so that I can trace certain parts of a drawing over and over again as I work toward an ideal design solution. Tracing also allows me to try different ideas without erasing part of a drawing I might want to refer back to later.

After I've gotten an idea of what the overall shape of my fixture will be, I begin sketching its key parts at full size. These details help me establish how I'll secure the reflector or diffuser to the fixture, how the wire and tubing will get through the wood parts, and tell me which joinery details I'll have to pay particular attention to.

Designing for Safety

Electric lights are so much a part of our lives that it's easy to forget they can be dangerous. An improperly wired fixture could cause shock or a fire. A com-

w bustible material like wood presents additional safety problems which make the use of some non-combusti-ble materials like metal, glass or ceramic inevitable in most wooden lighting fixture designs.

Underwriters Laboratories (UL) defines the safety standards for portable lamps and light fixtures. This independent, non-profit organization also tests light-

FIG. 1: DESIGNING WITH LIGHT

Ambient lighting fixtures spread low light throughout a room.

Glare occurs when a light source within the field of view is much brighter than the rest of the Kght within view. Everything else looks dark. Diffusers or km-wattage bulbs would correct the problem.

Ambient lighting fixtures spread low light throughout a room.

Was this article helpful?

0 0

Post a comment