We recently enclosed a doorway with drywall, after sanding we painted the whole wall with primer. We painted the entire wall with two coats but when the light hits it just right you can see the outline of the old doorway. How do we fix this?
It's tough doing this type of patch and make it perfect. The only way to fix it is to add a texture or recoat again with drywall mud, repaint and hope this doesn't happen again. You could try adding a little drywall mud to some primer; roll this on the patched area using a good back-rolling technique. This could blend it better but it might still show up.
I would put another coat or two of compound on the taped areas and make sure the compound is 1/2in. over the taped area on both sides, this allows the compound to be sanded down thin on the edges to have it blend into the wall. Then I would use a drywall primer (PVA) instead of a wall primer. I hope this helps