system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do wet clothes appear darker in colour when wet, even when water is colourless?

And further to this, why do some clothes appear see through when wet?
gpt
Water increases the scattering angle of light on fabric, and as a result, light is reflected and refracted in a greater number of "directions" than it is from dry fabric.  Your retina is therefore receiving less overall reflected light.  Since our sense of sight is simply a sophisticated means of making sense of a wide array of complicated light signatures, your brain interprets this as being darker.