I can see patches of wallpaper backing on walls after they were primed. Is there anything that can be done now? It was not noticeable until primer was put on – now walls look bad.
Couple of choices;
1- Scrap the areas where the paper is to remove it. You will need to apply some drywall mud to these areas, sand and spot prime before painting.
2- If the paper is tight (not bubbled) then you can apply some drywall mud to lessen their appearance. Pay close attention to the edges and feather out the drywall mud for the best look. Sand and spot prime before painting.
At this point all you can do is lessen the look of these areas. I suppose another option is to apply a texture to the walls to cover up the patches. This would work but will be more work.