DEAR TIM: I have a strange problem. During different times of day and at night, you can see strange shadowing on my new drywall walls. When I slide my hand over these areas they feel smooth, yet they appear uneven. This problem comes and goes with the changing seasons. Is there something wrong or should I schedule a visit to the eye doctor, as my wife suggests? R. S.

DEAR R. S.: There is no need to go to the eye doctor. However, I do suggest that you schedule an appointment for your wife! Your photographs clearly show to me that you are a victim of 'joint banding' or 'telegraphing', as it is commonly referred to in the trade. To make matters worse, your walls were painted with a gloss paint which magnifies the problem.

In order for me to explain just what is happening, I had to dust off my high school physics book. The root of your problem lies in light reflection. The light bouncing from your drywall is not doing so in a uniform manner. This is caused by several things.

While the surface of the drywall appears smooth to the touch, it is in fact comprised of two entirely different surfaces. The drywall paper itself has a completely different texture than the joint compound used to fill the joints and cover the nails and screws. Not only that, the paper and the joint compounds can absorb liquids unevenly. Herein lies part of the problem.

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When your painter applied the paint, the paint film was not able to adequately disguise these different textures. When light hits these surfaces at a low angle (morning and afternoon), it reflects differently from the paper and the joint compound areas. Because the paper has a slightly rougher texture than the joint compound, the light rays from the sun are scattered by the rough texture. The light bounces more uniformly from the smoother joint compound areas of the wall surface.
This problem comes and goes with the changes in seasons, because the angle of the sun changes in the sky. Your problem is evident at night because of the recessed lights in your ceiling. These lights cast direct light onto the wall at a low angle.

You can solve the problem very easily. All that has to be done is to create a uniform texture on the drywall surface that absorbs liquids at a uniform rate. Ordinary paints do not have this ability, for the most part.

Fortunately, there is a very simple way to enable the light to bounce uniformly from your walls. There are special paints which can be applied to the drywall that will perform this task. These paints contain special compounds which seal the paper and the joint compound so that they absorb subsequent coats of paint at a uniform rate. These paints also contain lots of small solid particles that fill the uneven texture of the paper to make a uniform surface.

Many of these paints are very affordable. Almost all of them are both easy to apply and environmentally friendly. They can also be applied to your walls, even though they have already been painted. Many of them have rapid drying times which allows you to apply the finish coat of paint the same day.

One final tip, try to use flat wall paints whenever possible. These paints, generally speaking, when viewed under a microscope, have a rougher texture than glossy paints. This rough texture enables them to trap the light rays and scatter them as they leave the surface of the wall. This scattering effect can often hide very small imperfections which would otherwise be visible had you used a glossy paint.