What's in a lampshade, you ask? Just about everything. A lampshade can make or break the décor of a room. It can decide just how much lighting a particular area of a room should receive, and thus, set the mood of the room. It can complement the lamp beautifully to make it stand out like a masterpiece and make a statement. Its color can give a room just the right amount of vibrancy it needs. There's so much a lampshade can do that it requires a guide for you to select just the right one. And here it is. A lampshade should ideally follow all the specifications shown in the image; these are more specific to table lamps than to floor-mounted lamps where the proportion of height and width to base may change. Keep in mind these tips when looking for a lampshade.

• To measure the size of the shade, measure the top diameter, the bottom diameter, the slant, and the vertical height, as shown in the image.
• The top of the shade should be wide enough to allow heat from the bulb to escape. The smaller the top diameter, the lesser the wattage should be.
• The shade should be tall enough to cover at least ½" of the neck of the lamp upon which the bulb is fixed. However, it should not be so tall that you have to reach inside the lamp to switch it on. The lamp should be placed such that it is at eye level, and no hardware should be visible at this level.
• The size of the shade also matters in terms of the purpose you are using the lamp for. If the lamp is going to be used as task lighting (reading, writing, etc.), the wattage of the bulb will be higher, and hence, the shade should be larger so as to not heat up and burn. Similarly, if it is going to be used for ambient lighting, you could go for a narrower shade and allow the light to illuminate through the top and bottom of the lamp.
• Finally, the placement of the lamp will also determine the size of the shade. It should not turn into a hazard every time you're trying to get out of bed or walk past a table. So, see the available area and choose a size accordingly.

While experts suggest that shapes should complement each other such that a round base should have a round shade, it is not mandatory. In fact, contrasting shapes such as an empire shape on a conical base (as shown in the image above) looks just as elegant. Similarly, choose a round shade for a rectangular base to create a bit of drama with your lamp. Quirky bases could have lampshades of simple shapes such as square or round, so as not to overpower the beauty of the base. The choice of color depends on two things: the overall décor of the room, and the purpose for which the lamp will be used. In a room with monochromatic colors, choose a colored lampshade to add a pop of brightness to the room. A colored lampshade usually does not help with task lighting, and if you want to use your lamp for reading, writing, etc., choose a light-colored shade made of fabric so that it can allow light to pass through easily. If your lamp is solely for ambient lighting or decorative purposes, knock yourself out. Go for a dark-colored hardback shade (a plastic liner laminated with fabric/paper) that provides a diffused look and creates a mood. While you may complement and contrast shade and base colors, you must ensure that the lamp doesn't become an eyesore in the room. So that's really all it takes to buy the perfect lampshade. When in doubt, ask your retailer for options, and you will be able to get a better idea of what will suit your lamp. Home decorating experts say that the lampshade you like is always the right choice!