A well chosen lampshade can enhance a whole room -- it becomes more important in the room design and helps direct the light. A poorly chosen shade, or one that is out of proportion to the fixture, can overpower the piece and detract from the beauty of the lamp itself. You can choose the right size lampshade by following a few design guidelines, mainly just a matter of measuring. An insiders' tip: In the lighting world, the lamp is the bulb and the base and the stand compose the fixture. When you consult a lighting professional, you'll get the best results by speaking her language.
The style of the shade needs to follow the style of the fixture. Typically, a curvy fixture suits a curvy shade. Similarly, a round fixture works best with a round shade, and a rectangular fixture with a rectangular shade. For a visual surprise, use the shape of the base stand as the shape of the shade. For example, a vase-shaped fixture typically sits on a rectangular base, so use this shape for the shade instead of the typical slant-sided or curved shade.
Calculate the correct basic shade height by first measuring the height of the fixture. Measure from the tabletop to the bottom of the light socket and multiply this distance by .65. For a floor lamp, the shade multiplier is .47 of the height from the floor to the base of the socket. For example, if the lamp's basic height is 24 inches, the shade should be a minimum of 15 1/2 inches high. The height of a slanted-side shade is measured along the slant; for a circular shade, the height is equal to the diameter; for a cylindrical shade, the height is the distance from the top edge straight down the side to the bottom edge. A shade with a curved edge is measured from the top of the shade straight down to the bottom edge. Insert a ruler inside the shade to obtain measurements on circular or curved-edge shades.
The diameter of the shade should be within 2 inches of the height measurement. For a 24-inch-tall base, a shade with a diameter of 22 to 26 inches is in good proportion. The size of a shade may be listed on the package by one number only, and this denotes the diameter of the shade. For example, a "16-inch" shade is 16 inches in diameter. The height may or may not be included in the package measurements.
Consider the amount and wattage of the light bulbs your base requires. A larger shade may accommodate a higher total wattage. Shades are labeled with the maximum wattage allowed, and using a bulb with wattage that's too high is a safety hazard. The number indicates the total wattage allowed, so if your base has three bulbs and the total wattage allowed is 60, each bulb may not exceed 20 watts. Consider also the size of the bulb you use. Incandescent bulbs may be shorter than fluorescent bulbs; check that your selected bulb will fit under the shade without touching the sides.
Put It All Together
The supplies you need to choose the right shade are a tape measure and your eyes. Measure the fixture, and from this determine the diameter and height for a suitable shade. Look at the style of the room and choose a shade that is in keeping with your overall design scheme and the shape and style of the fixture. For example, lots of fringe and tassels on a shade may not suit your contemporary room plan. Consider the room design, room color scheme and shade function when choosing a shade color. Lighter colors, for example, diffuse more light into the room than a dark shade. If you can, take your fixture with you to the store and try different shades. You're the one who has to look at it every day, so choose a lampshade that pleases your eye.