Question: The ceiling in my house is showing shadow or ghost lines that correspond to the longitudinal beams of the roof structure.

Apparently, humidity is causing the dark lines. I painted the ceiling three years ago to get rid of the lines, but they came back.

This time, I want to use the best paint that is available in the market.

Can you recommend a good ceiling paint that resists discoloration?

Answer: There are a number of ceiling paints fitting that description, including a group of new primer/topcoat combinations.

I used one of these for the ceiling of my home office that worked extraordinarily well and was low on volatile organic compounds, which meant odor-free.

I have long been a fan of Zinsser's BIN primer-sealer, which is not low-VOC (volatile organic compounds), because it is pigmented shellac. It does kill stains and stops knots in wood from bleeding through the topcoat.

I have used it regularly over the last 30 years in three houses, especially to cover water stains in ceilings caused by roof and pipe leaks after they had been repaired.

I stumbled on the product in 1985, when I was renting a condo in a resort community near Charleston, S.C. The hot-water tanks were in the space between the first and second floors, and what I assume was the high salt content of the water shortened the lives of those tanks.

The tank in our condo had been replaced before we arrived, but a couple workers showed up to repair the ceiling while we were there.

They set up plastic sheets for protection, and then sprayed on the BIN and returned later to repaint, while recommending the product all the time.

That's my experience.

What I suggest is that you go to a paint store or the paint department of your local hardware outlet and describe your needs.

I have had great luck recently with finding exact matches for paints to cover repairs on a wall without having to repaint the whole area.

Your problem doesn't seem all that extraordinary or unusual, and the retailers might have a way to keep the ghosts from reappearing in such a short time.