Which term describes a blotchy appearance caused by insufficient photons reaching the imaging receptor?

• A. Ambient noise
• B. Quantum noise
• C. Quantum mottle
• D. Photon starvation

Answer: (C)

When there aren’t enough photons reaching the receptor, the image shows a blotchy, mottled pattern. This happens because the number of detected photons per pixel fluctuates randomly, and with low photon counts these fluctuations become visually pronounced. The resulting mottling is described as quantum mottle. It reflects the quantum noise arising from low exposure. Ambient noise is unrelated to photon counting, and while photon starvation describes underexposure, the specific blotchy appearance is best termed quantum mottle.