What could cause an area on an analog radiograph to be darker?
1. Increased processing time.
2. Reduced attenuation of the X-ray beam in the patient.
3. Increased exposure time.
4. Reduced deposition of metallic silver on the emulsion

(4) only

All of the above.

(2) and (4)

(1) (2) (3)

(1) and (3)