What does bit depth represent?

• A. Number of gray values
• B. Number of colors
• C. Screen resolution
• D. Scan speed

Answer: (A)

Bit depth is the number of distinct tonal values a pixel can represent. In grayscale, that directly equals the number of gray values you can distinguish. Each extra bit doubles the possible levels, so 8-bit depth gives 256 gray values, 1-bit would be just black and white, and so on. In color images, bit depth is per color channel, and the total number of colors comes from combining those channels, but the core idea remains: more bits means finer tonal detail. This isn’t about how many pixels the image has (screen resolution) or how fast the image is scanned (scan speed). It’s also not simply “how many colors” in isolation—the number of colors depends on the bit depth across channels, whereas the direct measure of tonal detail in grayscale is the count of gray values.