In Photoshop, the adjustment that allows users to change the overall lightness of an image is the Brightness/Contrast adjustment. This adjustment is found under the Image menu by selecting Adjustments > Brightness/Contrast.
Additionally, you can use other adjustments such as:
- Levels - This allows for more precise control of shadows, midtones, and highlights.
- Curves - This gives detailed control over the image's tonal range and allows for adjusting brightness in specific areas.
- Exposure - This is used to adjust the exposure levels of the image.
Each of these adjustments can effectively change the overall lightness of an image, but the Brightness/Contrast adjustment is the most straightforward for a simple lightness adjustment.