Lyric discussion by FuriKitten 

Cover art for Red Light lyrics by Siouxsie and the Banshees

I would think it had nothing specific to do with pornography at all,

Merely a description of the fashion, model, celebrity industry and in particular the rise of models as celebrities as was happening at the time.

The red light is a photography 'safe' light that would on in the dark room, also be on the outside to indicate that the dark room was in use,

Come into this room Come into this gloom See the red light rinsing

The rinsing is washing the developer fluid of the film or paper to stop further development of pictures, A dark room is dark and gloomy (and smells of ammonia)

Kodakwhore and shutterslut are the same as we would use attention whore or facebook slut now

My Interpretation