do higher settings display weaker signal returns better like air bladders on a bass better? Yes for now with my budget i have an 8 level grayscale model which im happy with just getting adjusted to what everything looks like (like an airbladder on a fish)

Depends on the unit brand.

Typically contrast is just a display setting that specifies how much difference there is between the light parts and dark parts of the screen. But if you turn it up, it may make it easier to see lighter images on the screen.

Typically contrast is just a display setting that specifies how much difference there is between the light parts and dark parts of the screen. But if you turn it up, it may make it easier to see lighter images on the screen.[/quote

Will it show a fishes bladder better if i turn it up more?

Depends on the unit brand.

Garmin echo 101

Garmin echo 101

 

GAIN is the setting you adjust to make "stuff" display better on the screen.

 

Use a high enough setting to get the detail you want but not so much that the screen gets cluttered up.

Page 2 of the manual.