The influence of the surrounding space on the lighting conditions in a photographic scene

Abstract

Lighting conditions are one of the most important factors for good photographic exposure. In enclosed spaces, like a photography studio, we can control the light in several ways. We can adjust the type of light source, the shape of the light source, its intensity, and in some cases the colour temperature of the emitted light. The distance of the light source from the observed photographic scene affects the amount of light that reaches the desired target, and therefore the actual lighting conditions on the photographic scene. However, the environment surrounding the photographic scene is often overlooked. The light emitted interacts not only with the objects within the photographic scene, but also with any obstacle in the path upon which a light ray falls. Light rays can be reflected, partially reflected, absorbed, or scattered from any surface in the immediate vicinity of the scene, depending on the material properties of the objects they encounter. In the case of reflection, the observed scene is additionally illuminated by the reflected light, since the reflecting surface in the near environment acts as another light source. Lightabsorbing surfaces, on the other hand, do not affect the scene in the same way, since the light is absorbed and not multiplied by the reflection. Reflections from the surrounding environment can therefore affect the intended lighting conditions of the observed scene in ways that we did not anticipate. This study focuses on the influence of the surrounding space on the lighting conditions in an observed photographic scene by comparing the lighting situations in a scene from a photographic studio with a diverse environment and from a darkroom with minimal environmental influence. Halogen, LED, and xenon light sources are tested individually, illuminating the test scene with different intensities and colour temperatures. The illumination conditions at the observed photographic scene are described using spectrophotometric methods and image analysis to numerically describe the differences in uniform illumination of the flat scene surface. The results are analysed and compared to illustrate the influence of the surrounding space. Based on the results, guidelines for a suitable test environment in photographic research are proposed.