Which factor most directly increases the number of grayscale shades available in a digital image?

• A. Higher bit depth
• B. Larger pixel size
• C. Higher mA
• D. Longer exposure time

Answer: (A)

Grayscale shades come from how many bits are used to store each pixel’s brightness. Each extra bit doubles the number of possible brightness levels, so the total shades are 2 raised to the number of bits per pixel. For example, 8-bit depth yields 256 levels, while 16-bit depth yields 65,536 levels, giving far smoother tonal transitions and less banding.

Larger pixel size changes spatial resolution and how much area each pixel covers, not how many distinct brightness values per pixel can be represented. Higher milliamperes (mA) or longer exposure time affect the amount of light and the brightness or noise in the image, but they don’t change the number of discrete tonal steps the pixel can encode.