Ugly light gradiant in dark scene...

Hi,

I’m having problem with one scene of my movie. The scene is dark, but I got some ugly gradiant on the white wall at the back (you can see it in attachment). What kind of filter can I use to correct this ?



Also, the black t-shirt have some kind of distortion in it… The scene was to dark ? (sorry for the poor image quality, it’s for Vimeo and I used a bad compression.