Gamma settings and filter

[xXNightEagleXx]

Since i've never been in open ocean (thus without heavy artificial light influence) i would like if anyone could help me to set the gamma to reflect as close as possible the real life atmosphere. Is there any image or description to try to understand the visibility in open ocean? Usually i don't use movies as reference because i know that most of time movies are just movies......

About the filter, i would like to know how realistic they are? I mean if my knowledge doesn't trick me, nvg were invented in 1945, so did they had any sort of filter on their periscope to improve even a bit the visibility?

Thanks
NE