Yellow paint does not a happy Red make

Other Half calls me "Red."  This is a well known fact among his friends and family, some of whom have no idea of my real name.  They'll just ask him how Red's doing or if Red's going with him someplace, etc.  You get the picture.

Now my title makes more sense to you.  On to the story.

Trying to settle on paint colors for the master bathroom remodel wasn't easy.  For one, it's a tiny bathroom of about 35sf with no window.  I also wanted to stay true by using original 1930s colors.  Despite being a huge fan of Behr paint, they didn't have any collections I could use.  Eddie Bauer paints, Sherwin Williams, and California Paints offers historic colors by era/period.  I chose Eddie Bauer based on the wide color selection and ease of availability.  After choosing colors for the master bedroom and bath, I almost unknowingly made the mistake of painting them to match.   Other Half mentioned that he thought the colors would be too dark for such a tiny space.  Fortunately, I had only painted a small strip of color on the ceiling to see how it would look.  After further researching bathroom paint colors from the '30s, I found they are almost always white or a shade of white, even if other rooms are brightly colored.  Apparently, it has to do with presenting the image of cleanliness and sterility.  I regrouped and decided for the walls to use a white that has just the ever-so-faintest hint of grey in an eggshell finish, and to use Behr white ceiling paint.  I bought samples of Travertine and Gelato and painted about a one-foot square of each on the wall.  Both were too dark.  Next I tried Honeysuckle (just to see how a tan/white would look) and Oyster.  Oyster was exactly what I was looking for. 

When I did the drywall patches on the wall, the joint compound dried to a yellowy hue where it touched the existing paint, but stayed white on the new drywall.  This seemed odd, but I attributed it to the water content in the mud leeching something from the old paint.  Since this bathroom was constructed in 1984, I knew lead paint wasn't involved and the house never smelled of smoke so I wasn't concerned of nicotine stains.  Just as a good rule of thumb to prepare old walls for painting, everything had been washed about two weeks ago with a TSP solution.

Yesterday afternoon I was eager to get the ceiling done so I could continue with the walls.  It would make little sense to hang the sink and install the medicine cabinet without first painting.  Only the recessed toilet area and the sink wall will be painted now, waiting to do the rest until after the shower is built.  I cut in the ceiling, and about fifteen minutes later when I got the roller started, the cut-in was already yellowing.  I went ahead and painted the rest of the ceiling to see what would happen.  After drying, which should have been a brilliant, bright white, it was impossible to tell that I had just put on a fresh coat.  The ceiling was almost an ecru color.  There had been no patches done on the ceiling, so I was especially confused.  I went online and read a few articles, learned why the paint (both old and new) had yellowed and contacted Behr and Kilz to get further advice.  They both said to use Kilz Original if I didn't mind the paint thinner/mineral spirit clean-up, or to use Kilz Premium if I'd rather go the soap-and-water route, and to put a coat over what I did yesterday to seal in the old paint and any yellowing compounds.  I have a new gallon of Kilz Original, but will be swapping it for the Premium since I have no easy and safe method of disposing of the chemicals.  More time, more money.  Frustrating, but will all be worth it.  We'll see how it goes after priming.