The most common problem in photographing biological material is lack of contrast. As mentioned earlier in this chapter, it is necessary to increase the contrast in order to capture a good image. However, under certain conditions of illumination, the contrast may be too high. The range of light intensities between the lightest and dimmest regions is so great that it cannot be recorded with a single exposure. This situation is found in darkfield illumination where larger structures scatter more light than minute structures. When enough light is used to reveal the fine details of the smaller structures, the larger structures become too bright, making it impossible to see their interior details.