The color rendering properties of the light source used, or the CIE Color Rendering Index (CRI).This is the color impression of the total environment that the light source creates. The color properties of luminaires have two important aspects: An installation where light comes from only one direction will result in harsh shadows and poor modelling. Modelling ability is particularly important in providing a pleasant overall impression of the athletes and objects in the field of play, not to mention of the spectators in the stands. Modelling refers to lighting’s ability to reveal form and texture. The lower the glare value, the better the glare perception for the players in a sporting event.Ī maximum GR value of 50 is generally specified for sports projects. Glare is a subjective factor for which CIE has, on the basis of extensive field research, developed a practical evaluation system for use in outdoor sports applications (CIE 112 Glare evaluation system for use within outdoor sports and area lighting).ĬIE 112 defines a so-called glare rating factor (GR) ranging from 10 to 90 on the assessment scale. This is called the uniformity gradient.Ī common uniformity gradient value for both horizontal and vertical illuminance in the direction of main cameras of ≤20% on a 4m calculation grid might ensure smooth panning between one area to another. The illuminance uniformity for TV/film coverage at a certain grid point thus has to be expressed as a percentage change from the average adjacent grid points.
This problem is most likely to arise when a television camera pans. In televised situations, high uniformity is necessary for smooth and natural-looking scenes, especially in this era of HDTV horizontal illuminance is generally 0.8, whereas vertical illuminance in the direction of fixed cameras requires a uniformity value of 0.7 (Emin/Eaverage).Įven when the uniformity ratios as we’ve defined them are acceptable, changes in illuminance can be disturbing if they happen too quickly. In non-televised situations, the uniformity of the horizontal illuminance is generally specified as between 0.5 to 0.7 (Emin/Eaverage) depending on sport and lighting class. the ratio of the lowest to the average illuminance (U2 = Emin/Eaverage).the ratio of the lowest to the highest illuminance (U1 = Emin/Emax).If uniformity is inadequate, certain objects or player details might be difficult to see from certain positions. Television broadcasting generally calls for an average Ev of between approximately 1000 lux and 2000 lux.Įnsuring uniformity is important in avoiding adaptation problems for both players and spectators. Televised events involve exceptions to this rule of thumb vertical illuminance has a major influence on the quality of a final television or film picture. For sports with no specific vertical illuminance criteria, vertical illuminance will be sufficient if the required horizontal illuminance is achieved, and if the lighting design rules are followed.
To guarantee an optimal view and make it possible for the human eye to identify players from every direction, we should generally measure Ev at a height of 1.5 meters, which corresponds approximately to the faces of the players.Įxperience shows that there’s an intimate relationship between vertical and horizontal illuminance. This means that we need to keep vertical illuminance (Ev) primarily in mind when we light them. The athletes in any particular sporting event, as well as the ball they’re using, can be understood as vertical surfaces. The horizontal illuminance shouldn’t be less than half the vertical illuminance or greater than twice the vertical illuminance. For televised competitions, the vertical illuminance level is more important than the horizontal illuminance level to ensure that the television picture has a well-balanced brightness, the ratio between the average vertical and horizontal illuminance should match as closely as possible, but shouldn’t exceed a 0.5 to 2 ratio. It serves primarily to create a stable visual background against which the eye can discern players and objects.įor non-televised lighting classes, an average horizontal illuminance of between 50-100 lux and 750 lux is required, depending on the sport in question and on the lighting class. Horizontal illuminance (Eh) represents the illuminance on this horizontal plane at ground level. The illuminated playing surface takes up a major part of the field of view for anyone in a sporting venue, whether players, officials or spectators.
0 kommentar(er)
