What graphical option is used to change the brightness or darkness of an image?

The option that refers specifically to adjusting the brightness or darkness of an image is primarily associated with the term "Brightness." Brightness controls the overall lightness of an image by adjusting all the pixel values in the same way, effectively making the whole image lighter or darker while preserving the relationship between colors.

Brightness is a fundamental tool in image editing, allowing users to enhance details in shadowy areas or reduce overexposed highlights. It directly impacts how an image appears in terms of light, which is essential for achieving the desired visual effect.

While terms like Exposure, Contrast, and Gamma also relate to image adjustments, they serve different purposes. Exposure typically changes the amount of light that hits the sensor in the camera, affecting how an image is captured rather than altering its appearance post-capture. Contrast deals with the difference between the light and dark areas of an image, making shadows darker or highlights brighter without uniformly brightening or darkening the entire image. Gamma affects the luminance of midtones and is more about adjusting the non-linear representation of brightness throughout the image, making it a more complex adjustment.

Thus, the choice that best defines the action of modifying overall brightness or darkness is the term "Brightness."