You may think that any paint labeled "Ceiling White" would be pretty much equivalent from brand to brand, but that's not the case. If you don't have the original paint can to check the brand of existing paint, there is no way to be certain a ceiling white will be the same. That means instead of a few simple touch-ups to cover some spots, you may be facing the bigger job of painting the entire ceiling.
Pigments and Color Difference
The most obvious reason for a difference in a ceiling white paint you purchase and what you already have on the ceiling is pigment. Each producer can use different materials to pigment the paint, processed differently and in different amounts. Even the same manufacturer can make changes over the years.
Environmental factors, such as cigarette smoke, can mean even the same brand's paint won't match what's there. Age can impact color, too. White pigments can turn yellow over time, though in areas that get ample sunlight, this is less pronounced, as the sun has a bleaching effect. The impact of these factors is that even if you have the original can, the paint won't look the same if you painted the ceiling some years ago.
Matching the Existing Color
A way around having to do the job over again is a careful color matching. Start off with some white swatches from the paint store. Whites come in an enormous range. One of these whites is almost certain to match your existing white on your ceiling. Check the swatches against the ceiling in good light. When you find the one that matches, it's a good idea to just get a small sample of it, dab it on and wait until it dries.
Prepare the Surface
Once you have your matching color, prepare the area well. If your touch-up is due to water spotting or some other kind of leak, an alcohol-based primer sealer is good way to prep the area. A bit of regular primer will ensure a cleaner finish. Failure to address an underlying problem, whether it be water or irregular surface, means the white may not look the same even if you have successfully matched the color.
Bill Brown has been a freelance writer for more than 14 years. Focusing on trade journals covering construction and home topics, his work appears in online and print publications. Brown holds a Master of Arts in liberal arts from St. John's University and is currently based in Houston.