Primers are formulated to produce a solid base, seal stains, and help bond the top coat to the wall. Both alkyd and latex primers provide good coverage and do a great job. Which one you choose will depend on the top coat you have selected.
Likewise, go with good quality, brand-name primers and paints, like Sherwin-Williams, Pratt and Lambert, Benjamin Moore, or Pittsburgh Paints. Better yet, visit a professional paint supplier and talk to the knowledgeable employees. They can give you useful tips and help you get the paint system (primer and top coat) that will work best in your climateand for the job you're doing.
Here are some important priming tips:
If the walls and ceilings were heavily prepped and the first coat did not do the job well and there's a light bleed through, apply a second coat.
• Some climates, especially those near salt water, need a second primer coat.
• Closely work with your paint supplier. Some primers are best for wetter rooms like bathrooms and laundries. Meaning, one primer doesn't necessarily fit all conditions.
Older homes that were constructed without vapor barriers will need a primer that seals and stops moisture from getting under the paint and causing peeling.
Plaster walls and drywall are different and normally require different primers. Consult your paint dealer for the ideal type that matches your walls and conditions.
Interior wood trim may also need different primers. Your paint dealer can also lead you in the right direction in this area.If you have primed over unpainted drywall or wood trim, you'll probably have to lightly sand after the primer has dried. Primer tends to raise the fibers or grain so a light sanding is needed before painting the top coat. Make sure to run a tack cloth over the sanded area so no dust is left on the surface.
Don't spot prime problem areas on walls that you've had to go back and work on. Those areas would often show through. Correct the problems and then recoat the whole wall. Luckily, ceilings are more forgiving and never show spot priming as much. There are also special paints developed for ceilings that cling to textured surfaces better than wall paints. Check with your paint supplier for what works best on your kind of ceiling.
If you prefer a darker top coat, tint the primer coat to match. It could save you having to apply a second top coat.