DIY Touch Up Wall Paint

Touch–ups on walls and ceilings painted long ago can sometimes create a more unsightly finish than the old paint itself. To avoid this it's important to use the original paint only, for retouching existing finishes.

It's also important to realize that any white will not match any white. There are hundreds of shades of white paint available from dozens of manufacturers. And what about semi–gloss, eggshell, high–gloss, oil–based, etc. Can these finishes be retouched successfully? As a general rule, only flat paint can be retouched without "flashing".

What is Flashing?

Flashing is a term used by professionals to describe the obvious difference in finish that will occur when retouching old or shiny paints. Flashing is most obvious when viewing a surface from the side. Look down a wall while standing at one corner of a room. You will see all the imperfections in the surface when light is reflected off it. Any difference in the overall finish is called flashing.

Flashing will also occur when a shiny finish is applied over bare wall patches. Wall repair mud and spackle must be primed with a flat latex before finishing with a shiny paint. If you're using flat for the finish it will be self–priming.

If you suspect that the irregular appearance of your walls is caused by failure to prime wall repairs before applying a shiny finish, coat the spots with flat and then touch up the shiny finish.

Choosing Paint for Touching Up

If possible, always use the original paint. That is, the can leftover from the original job. If the original paint is not available and it is a stock color (a premixed color made at the factory, not mixed at the store) then a new can of the same color will most often work as well.

Custom mixed colors will usually not match the original paint. The problem is the accuracy with which the color is mixed at your local store. Different people, operating the same machine, will use slightly different amounts of tint. All it takes is a tiny change in the amount of tint to change the color enough to show on the old finish. Even computerized machines can produce enough of a difference in the mixed color to cause a mismatch. If you must get a new batch of paint, check the color for matching before proceeding with your retouch job.

Fixing Flashing

When you have a flashing problem with your touch–up job, the best solution is to paint a whole wall from one break to another. This "Paint from Break to Break" method will diminish the noticeable difference in the new finish if the color is not exactly right.

A break in a wall is usually the corner but can also occur when trim molding stretches from baseboard to crown molding. The molding breaks up the wall into isolated sections. An isolated section like this can be repainted with a closely matching color and the minor color difference will not be noticeable. Wall corners work well as breaks because the two wall surfaces reflect light differently, making it hard to see varying shades.

Touching Up Flat Paint

Make sure your paint is mixed well before putting it on your walls. Shake the can or stir just before using it. Retouch using a brush on small areas and a roller on larger spaces. See Brushing Techniques and Rolling Techniques for more about application.

Check to be sure the touch–up is blending well with the original finish. Touch up a small area and wait for it to dry completely. Use a hairdryer if you're pressed for time. When it is completely dry, examine the finish while looking down the wall. If you can see the spot where you applied the new paint, then your touch–up job will not look very good. If this is the case, use the "break to break" method described above to touch up.

Touching Up Shiny Paint

Shiny paints can be the most difficult to touch up. This includes eggshell, semi–gloss and high–gloss, as well as any oil or alkyd–based paints. Even flat oil and alkyd will flash if you try to touch up in the middle of a wall or ceiling. For all these finishes use the "break to break" method to freshen the finish. Original paint or not, the only way to avoid a flashing problem is to do a whole wall.

Touching Up Trim Molding

Trim should be treated in the same way as shiny finishes, painting from one break point to another. Break points for trim are the points where two separate pieces of molding come together as at the corners of a door or window frame. The corners of an individual piece of trim molding can also form a break point between the edge and the face of the molding.

To touch up on a door casing, for example, do the case molding on one side, from where it meets the floor to where it meets the top of the frame. Don't touch the edge of the casing where it meets the wall, just do the face. The touch–up will not be noticeable because the edge is seen at a different angle than the face of the molding.

Dealing with Stains

Touching up the paint is one thing, but stains present another problem. Some stains will bleed through the new coating if they aren't sealed first. Water, ink, cigarette smoke and grease stains will all ruin your touch up job. Use a shellac–based sealer to block these stains before touching up. It may be necessary to do from one break to another when treating stains like this. See Repair Tips for Stains and Repair Water Stains for more.

Shellac sealers dry very quickly (about half an hour) and will block almost any stain with the exception of tannin from redwood trim. Redwood is not commonly found in new homes but historic homes will often have redwood trim that has been painted. When tannin from redwood bleeds through the finish, use a water–based sealer like Kilz2® to block the stain and then touch up as described above.