Changing which of the following would not cause any change in a hard copy image output?

• A. TGC
• B. Overall gain
• C. Output power
• D. Display brightness & contrast

Answer: (D)

Hard copy output is determined by the actual image data after processing, which reflect the echoes received and amplified through the system. Factors that alter the signal amplitude along the path will change those pixel values and thus the printed image.

Time gain compensation changes how gain is applied at different depths, reshaping brightness across the image. Overall gain multiplies all echoes together, uniformly shifting brightness. Output power changes the transmitted energy, altering echo strength across the image. All of these modify the underlying data that the printer uses to generate a hard copy.

Display brightness and contrast, on the other hand, only affect how the image is shown on the monitor. They don’t alter the stored pixel values or the data sent to the printer, so the hard copy remains unchanged by these display adjustments.