Anyone who has painted an interior or exterior surface has saved some paint for touch-ups. The Product Stewardship Institute estimates that Americans stockpile 34 million gallons of leftover paint every year, earmarking most of it for touching-up previously painted surfaces.

Some do-it-yourselfers are so eager to repaint every ding, nick, or scratch that they have poured paint into washed-out roll-on deodorant bottles, cleaned-out plastic squirt catsup bottles ,or scoured-out dab-on shoe polish applicators for immediate touch-up. Yet, touch-up that doesn’t show is hard to achieve.

Problems with Matching Color
With time, all painted surfaces will lighten in color. Some paint colors — particularly bright colors, and especially reds, blues, and yellows — are vulnerable to ultra-violet radiation.

Older painted surfaces are likely to be chalky. Chalking is a form of paint oxidation that occurs as paint weathers and the binder breaks down releasing the binder’s hold on the coloring pigment.

Bleach, peroxide, ammonia, and alkaline cleaners also change the surface color through chemical action on the paint pigments.

Doing the Touch-up
Begin with paint that is free of lumps and particles. Paint that has been stored may oxidize, forming small globs. Stir the paint thoroughly for color consistency. Strain interior paint through nylon mesh and exterior paint through fine window screen.

The Paint Quality Institute recommends doing the touch-up when temperatures are within about 5 degrees Fahrenheit of the original application temperature.

To maintain the same texture do the touch-up using the same applicator — brush or roller. Begin with a dry brush loaded with a tiny amount of paint, feather it out in all directions around the area being touched up. Thinning the paint slightly with water will reduce brush marks. If the paint was originally rolled, use a smaller roller with the same nap to blend in the repair paint. If the surface was sprayed try doing the repair with a foam brush.

Before repainting a “painter’s holiday” — a missed spot — let the surrounding surface dry to avoid brush strokes. Also, let thoroughly dry any surface that has been scrubbed and rinsed.

When touching up a gouge, repair the surface with spackle and sand it smooth and flush with the surface. Dab on primer, then repaint. Without the primer, the differing porosity will make the touch-up look like a lower sheen paint.

After it dries, if the touched-up area looks darker than the original, sand it down, dilute the latex paint slightly with water and re-touch.

Flat sheen paint has less reflection than eggshell, satin or gloss, and is the easiest to touch-up.

The Biggest Hurdle
The biggest obstacle to accurate touch-up isn’t technique but personal memory. Considering that various shades of white are the most used interior color, think of the difficulty trying to remember which room is alpine white, glacier white, or snowy white.

To help you remember simply write the color name on the back of a switch plate in the room where it is used, and to write the name of the room on the bottom of the paint can.

Eliminating the Match
Sometimes the touch-up area is big, sometimes it is at eye level, and sometimes it is in bright light. At these times forget about blending in a seamless match. Instead get creative.

Turn the wall that needed touch-up into a focal point or accent wall by painting it a color that complements the room rather than matches the other walls.

And while accent walls are not the norm on exterior surfaces, remember that for exteriors all you need is to come close to the original color because no one will see all four exterior walls at once.

Too Much Paint for Touch-up
If you have more paint than you need for touch-up, bring it to Metro. Metro operates two permanent household hazardous waste facilities where you can bring up to 35 gallons of household hazardous waste for free. Besides oil and latex paint, Metro receives pool and spa chemicals, pesticides, automotive products, cleaners, and sharps. The facilities are open 9:00am to 4:00pm Monday through Saturday and closed on major holidays.

Paulette Rossi is a Certified Master Recycler and freelance writer living in Portland, OR.