I am looking for some help and advice regarding a shadow line on my newly plastered ceiling. I have a large living room, roughly 20ft long by 13ft wide and have just had it plastered. While the plaster was wet, it looked brilliant and I thanked the guy who did it for doing a good job. Then it dryed and a few imperfections showed, but still looked good. But after painting white and refitting the lights there is a shadow line right across the room (following a joist I believe). Now I hate it and wondered if I have any options apart from another skim.