Final answer:
To increase image contrast, the compression control should be adjusted on the scanning console.
Step-by-step explanation:
When you want to increase the image contrast to produce a more black and white image on a scanning console, you would adjust the compression control. Increasing compression on the console will enhance the contrasts between the bright and dark areas of the image.
It is important to differentiate contrast from brightness, which can be adjusted by altering the overall gain. Besides compression, other controls like rejection might be used to ignore the lower-level echoes, but compression specifically alters the dynamic range to enhance the contrast of an image. Reducing demodulation is not typically related to contrast adjustments.
When adjusting the console controls, always ensure the final image meets the diagnostic requirements without compromising important details.