Yes, exactly. If to look at Lowrance and Humminbird side imaging screen shots that are in Internet 99.99% of them are with black background - i.e. water is black….why?:
https://www.google.com/search?q=lowr...08.q1uQwD1tl1w
https://www.google.com/search?q=side...25._negRHQF0-M
Only big colored dots and stripes can be seen on black background. To see white water column is more habitual and informative.