As an addendum to the previous post, I’ve gone through a number or sources for the various depths at which the various colors will no longer be discernible underwater. For most freshwater rivers and lakes color loss underwater will be at approximately:
- Red ~15-18 ft (5 m) (note: after 5 m ~ 90% of the intensity of red is gone)
- Orange ~ 25-33 ft (10 m)
- Yellow ~ 35-45 ft (10-14m)
- Green ~ 70-75 ft (20 m)
- Blue ~ 110 ft (30-33 m)
- Purple ~ 75 ft (20 m)
These numbers are for clear water only, depths will be shallower with the introduction of particulate matter, organic materials, tea stain etc.
A special note on Fluorescent Colors
An object that is fluorescent emits light of a longer wavelength after absorbing light of a shorter wavelength. Thus, a fluorescent lure that appears chartreuse/yellow in color is absorbing light in the green-blue-ultraviolet portion of the spectrum – i.e. colors that are available at greater depths! This is why fluorescent colors can be seen at greater depths than normal. Fluorescent colors also work particularly well on cloudy days, when the visible light spectrum is diminished but UV light (short wavelength) is still quite strong.