Final answer:
Contrast refers to the difference in brightness and colors between areas of an image, crucial for creating depth and definition in the visual arts and microscopy.
Step-by-step explanation:
The need for contrast is a difference in brightness between adjacent areas of an image. In any visual art form, contrast plays a crucial role as it defines the difference in colors, intensities, and tones to create interest and depth in the piece. An example of high contrast can be seen with the use of black and white, which creates a stark and powerful visual effect. Conversely, low contrast is where variations between light and shade are much less pronounced, such as in Hiroshi Sugimoto's Cliffs of Moher (1989), where the image is composed of similar shades of grey and lacks stark differences. In microscopy, enhancing contrast is essential for interpreting images clearly. This can be achieved through stains or wave interference techniques, which manipulate light phase and refraction to highlight the object against its background.