The growth of the plants increases with increasing light intensity and exposure time up to a limit, beyond which the development cannot be increased. The first principle in orchid care is therefore, to give the plants so much light, how they tolerate without damage. In nature, moist air is achieved through constant movement, that the plants remain relatively cool despite the intensity of tropical sunlight, so not be harmed. We do not have this important air movement; compensation is only possible through reduced exposure to light.
In general, we need to keep this in mind when caring for tropical orchids, that in their homeland the light is much more uniform, both in the course of the day and the seasons, than in the temperate zone with its constant change in climate. The tropical day has 12 Hours of daylight and 12 Hours of night, the position of the sun is evenly high in the course of the seasons. In contrast, the day length is differentiated with us, the position of the sun and thus the light intensity vary within wide limits. Orchids are extremely adaptable; otherwise their existence would be impossible under such greatly altered lighting conditions.
Outwardly visible effects of light on the plants are explained below. Undamped sunlight, especially behind glass in narrow air spaces, can damage the plants due to excessive heating. They show a more or less strong yellowish color due to the bleaching of the leaf green (Chlorophylls) or by direct burns to the bulbs and leaves. They turn brown or black, and with that a part is created- or total loss, so damage, which cannot be fixed again. One can easily save oneself from it. Plant parts, which feel extremely warm beyond the air temperature, are in danger. More shade reduces the exposure to light and lowers the temperature through air humidification and ventilation.