Lava pools in the Nether looks strange

[depressed-pho]

This has happened since #6. I totally forgot that there was a ever-lasting thin fog there, interfering with the desaturation effect quite badly. The primary reason for the effect is that during a bad weather the intensity of sunlight goes down so particles flowing in the air (i.e. fog) starts to desaturate the scene. See https://en.wikipedia.org/wiki/Aerial_perspective

Perhaps the filter should not affect areas affected by torch light?