Which factor increases the number of gray values in a PSP image?

• A. Bit depth
• B. Exposure time
• C. Plate size
• D. Display brightness

Answer: (A)

Gray-level resolution in a PSP image is determined by how many bits are used to code each pixel. The number of distinct gray values equals 2 raised to the bit depth. So more bits per pixel mean many more possible gray levels, giving finer contrast and detail. Increasing bit depth directly increases the range of gray values (for example, 8-bit gives 256 levels, 12-bit gives 4096, 14-bit gives 16384, and so on).

Exposure time affects how bright the image is and can shift the histogram or even cause saturation, but it doesn’t create more gray levels. Plate size changes spatial resolution—the number of samples across the image—not the number of gray levels per pixel. Display brightness changes how the image appears to the eye but not the actual encoded gray values.