This shot was taken when I was photographing a Lindy hop festival. The error occurred because I took this indoors when my camera was still set to outdoor settings.
The ‘look’ of the shot is (I think) due to the white balance setting, ISO noise and a high F stop.
There is no post processing other than some tinkering on Lightroom around highlights, lowlights etc. Nothing more than you would expect for the average image, and absolutely no filters.