Bring Back RedBeta

Four sites, measured

Distance, not depth, decides the color

Red disappeared by 3.4 meters of water at a shallow Mediterranean site and survived past 10 meters on a clear Red Sea wreck. The depth gauge cannot explain both.

Nearest zero
3.4 m
Furthest survival
>10 m
Dive sites
4

The water between subject and lens is the path that matters

A fish one meter from the camera and a reef eight meters behind it share one frame but not one optical path. Across a measured scene spanning 6.5 to 29.7meters, the water's blue-channel effect varied by 254 times.

What the four sites showed

SiteWaterRed measured zero
MichmoretShallow coastal greenBy 3.4 m
NachsholimGreen, five metersBy 4.1 m
KatzaaTropical, 10 to 15 mAt or before 6.1 m
SatilTropical, on a wreckAt or before 10.2 m

Source: SQUID, the Stereo Quantitative Underwater Image Dataset, IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020. DOI 10.5281/zenodo.5744037.

Read the full measurement method