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Studio with continuous visual work

For rooms where special continuous work is carried out, the main lighting goal is to meet the needs of the work.

Illuminance Working lighting usually refers to the minimum illumination value required for work. This is stipulated in the British Illuminating Engineering Association (hereinafter referred to as the Illuminating Association) regulations. The values recommended by the Illuminating Association documents are often misused. Professionals and lighting installation designers must understand that the illumination values referred to in the regulations are minimum values, not design goals. For example, there are two fundamentally different operations: typing bold on white paper and using pencil on blue paper. The clarity obtained under the same illumination is very different. The Illuminating Association regulations cannot have special regulations for all possible changes in work and environment. Therefore, when understanding the data recommended by the regulations, lighting professionals must still judge based on their own skills and experience.

When selecting the design illumination value, attention must be paid to the statutory documents related to lighting. The documents stipulate the required amount and suitability of lighting. The required amount refers to the working illumination, and the suitability includes direct discomfort glare, reflected glare, spectral properties of the light source, and lighting direction.

Direct discomfort glare Since 1961, the degree of direct discomfort glare has been numerically calculated, which is what is expected of general lighting installations using ordinary lamps. This value is the glare index. British lighting association regulations set the upper limit required for various working situations, and the prescribed limit varies with the difficulty of the visual task. The more delicate the work, the lower the glare index value is required.

This means that the lower the glare, the higher the requirements for lighting facilities. It is also equivalent to having no brightness contrast. Many lighting professionals believe that this will cause visual monotony and is as unsatisfactory as excessive glare. The lighting association's recommendations are a compromise between the contradictory requirements of controlling glare on the one hand and the pursuit of variety and beauty on the other.

Reflected glare It is known from experience that light sources can reflect light on shiny surfaces such as walls, desks or the work itself. In some cases, we also want a little reflected glare. For example, when reading on a micrometer, if there is a bright reflection on the polished scale, it is easy to see the dark scale, but in general, we always do not want reflected glare. Reflected glare sometimes makes people feel uncomfortable, but more because it has an adverse effect on vision. Appropriately changing the position and direction of the table relative to the light can reduce glare, and it can also be reduced by selecting lamps with appropriate light distribution or polarized light.

The most suitable method for expressing the appearance effect of indoor lighting is to indicate the value of the luminous flux required on each boundary surface of the room, and to indicate the value and direction of the luminous flux required by the objects or people in the room. For many years, scientific research has been seeking the proportional relationship between these luminous fluxes. This relationship can be expressed as the ratio of illumination to reflectivity, or as the ratio of the brightness that the observer can see. The results of scientific research have announced general numerical limits. However, experience in lighting design tells us that even if the same lighting equipment is used, if the surface reflectivity of the two rooms is very different, or the size ratio of the two rooms is very different, the appearance effect is often very different. It can be seen that for a perfect photographic effect, there must be a more detailed technical specification than the above set of proportional values.

This technical specification is generally expressed as the brightness ratio of the room boundary surface, which is formulated based on the visual effect produced at the most important observation position in the room; and it must be verified by the results seen at the main observation point in the room. In many rooms, people and furniture may be more important than the room surface in terms of visual perception. This point must be taken into account when formulating the luminous flux distribution.

Recently, engineering and technical personnel have summarized the following rules of thumb for guiding aesthetic design in lighting identification work:

(1) If the reflectivity of any indoor surface is less than 15%, increasing the amount of light on the surface does not necessarily affect the visual perception of the surface.

(2) If a variety of lighting equipment is used, a room with pleasant color contrast will appear more beautiful.

(3) If there is no satisfactory color contrast in the room, it is necessary to use light to create brightness contrast.

(4) Weak light contrast is generally not noticeable.

Color table and color rendering When visual work includes color matching identification or color discrimination, the spectral quality of the light is very important. As for other work environments, whether it is to create a satisfactory beautification effect or to provide the necessary lighting to achieve satisfactory visual clarity, the advantages of different light sources must be carefully studied.