There are two kinds of electric illuminants: one is heat radiation illuminant, for instance: incandescent lamp, halogen tungsten lamp, low-pressure halogen lamp; another kind is gas discharge lamp, for example: fluorescent lamp, high-pressure fluorescent mercury lamp, low-pressure sodium lamp, metal halide lamp. Gas-discharge lamp is made under the theory that gas discharges when current goes through it . The radiation features of all rights are not the same, and the radiation power is not the same according to the wavelength distributing. This property is spectral energy distribution curve.

      Normally, the greater power, the higher efficiency illuminant will have. For low power illuminant, the efficiency is lower than same illuminant with bigger power. High-pressure sodium lamp has the highest luminous efficiency.

      The lighting effort in indoor decoration and indoor design is what we cannot overlook. We knows that, light is very important to people. Modern scientific research proved that, 80% information is catch by eyes when human getting information from the world, and only through light, we can see various shapes images and the colorful world. So, if no light, there is no image and color. In modern indoor decoration, most part of the beautiful decorations is express by light. From here, we can say, light is the soul of indoor decoration, for example, dividing space, gaining arrangement, and creating atmosphere etc. 　

      Apply lighting for decoration is not start today. We can call it the beginning of using light for decoration from a certain sense when Edison invented electric lamp one hundred ago. With constant development of human society and the rapid development of science and technology, various artificial illuminants had been developed, and the instruments for using light for decoration is changing too, new lighting decorations come one after another. So, how to make good use of lighting for decoration? 　

      Before design lighting arrangement for your rooms, please make sure all functions of each house, and make sure environment atmosphere the room need according to different purposes. For example, living room needs to be bright and kind; bedroom needs comfortable and private. Then choose certain illumination for every room purposefully according to your demands. Illumination, in plain language, is illumination intensity of the place that being lightening, the unit of this is LX. We may need different illumination in different business. In a room, 20X is enough for distinguish figure of an object; illumination for entertainment is around 150~300lx, illumination for reading is 500 to 1000 LX. Illumination indoor should be arranged properly, too bright or too weak light does no good to eyes. 　　

      After settled the illumination, the next important step is to choose suitable illuminant. When choosing illuminant, first of all, you should consider the color effect and mental effect. Illuminant has cold light illuminator and warm light illuminator. Because cool and warm light will give people different feelings. Comparatively speaking, warm light illuminant will give a feeling of warm, comfortable and kind; cool light illuminator will give a feeling of cool, open and bright. In ordinary families, incandescent lamp is warm light and fluorescent lamp is cool light. It is also very important to choose the color of illuminator, because different color light will give people different feelings. Besides, some color light will change the color of the objects when shining on it, and different colors will produced another colors when overlay with each other. By the way, light color is not the same as the color of objects. You will get black when putting tricolors of object folded, but you will get light gray light when putting tricolors of light. Putting other colors together will also have different colors; you can test it by yourself. By applying different colors of light, you can produce many atmospheres; it is an important measure and high-class decorative means in indoor light environment design.

      While using light for decorations, there is a most important step, it is to make sure lighting mode. People should choose right lighting type according to different demands of room. Then, which illumination types can be divided? Generally speaking, there is two ways for the classification for lighting: First, according to the lighting mode, lighting can be divided into direct, indirect, diffusion light, half indirect, indirect. Second, according to illuminate scope, lighting can be divided general lighting, regional lighting and mix lighting. These two kinds of lighting modes both have its one’s own uses. Use these lighting systems ingeniously; we can create different ornament results indoors. For example: We can produce soft atmosphere with diffusion illumination, then use partial lighting in the important place, so we can reach the purpose of projecting subject, drawing back levels and attracting sight. 　

      Finally we come to light fittings choosing. Though we are talking about how to use light for decoration, most of the time decorative effect decide the lamp. One fine lamp can become " a precise pen "in room decoration. The selecting of the lamps can in accordance with the host’s taste but be careful that it must harmonious with the style of the whole room.

      Besides the above decorative means, there are some special means for light decoration. For instance: Use the neon lamp of different colors to be made into the artistic model, and use them for room decoration; utilize fiber to make artistic lamps, which can give people fantasy feeling; and there is “light artware” that combine with different plastic arts with various kinds of lights. In a word, with scientific progress, various kinds of new technologies are being produced constantly, and the means for using light for decoration will be richer. 　　

      Use light for decorating room is an ornament skill that hard to learn, but if use aptly, the result that it produces will be marvelous.

4　 How to choose the color of light
      In family house, the illumination becomes very important. If you do not pay much attention to this, you will not find too much image about the color of light. When choosing bulb or lamp tube, maybe you just care its power but not its color. In fact, the color of light has much to do with the atmosphere. So, to choose the color of light is one very important thing in room decoration. At present, there is two kind of electric illuminant for family purpose; they are incandescent lamp and fluorescent lamp. The former is irradiating by heating up tungsten filament, the temperature is relative high and belongs to warm illuminant, and the color has a little yellow. Fluorescent lamp is irradiating by gas discharge when electric current goes through it, so the temperature is relatively low and belongs to cool illuminator; the color of the light has a little blue. In resent years, many new fluorescent lamps had been developed. Besides the original colors, there is also tricolor fluorescent lamp close to natural lights. Meanwhile, energy saving lamp raise suddenly as a new force in lighting industry, there are many colors and also you can choose warm color and cool color, the room for selecting is relatively larger.