1. Hardback lamp shades are made by laminating fabric or paper to a translucent or opaque plastic liner. Fabric is curved around top and bottom wire rings called spiders and glued together at a seam - hardback shades are not washable.
2. Drum lamp shades measure at least 1 inch smaller at the top than the bottom, and length equals the bottom diameter; oval, square, and rectangular shades come in various proportions. Empire lamp shades gradually slope outward from top to bottom, and coolie shades have a dramatic top-to-bottom outward slope.
3. Silk lampshades are not always made of silk fabric; silk shades have an inner fabric lining and an outer fabric that is stretched over a side and top wire frame. Most silk shades can be washed in warm soapy water, and they have a longer life than hardback shades.
4. Lamp shades should be selected according to your light requirements in a specific area of a room. Translucent white or ivory shades emit a soft light that radiates for several feet, while opaque shades focus light downward and are best for reading.
5. Proper shade size is important to the balance of lamps; improper sizing can make lamps seem top- or bottom-heavy. The height of a shade should never exceed the height of the lamp's body, and it generally measures one-third the height of the lamp body.
7. The harp of the lamp is the U-shaped wire that attaches the shade to the lamp; shorter lamps have shorter harps, and larger lamps have larger harps. Lamps with multiple sockets require exact sizing for appearance and safety reasons.