Does Paint Get Darker or Lighter When It Dries? Here’s the Deal

When I operated a furniture finishing business, I often encountered the problem of color matching in the spray booth. I’ve also done my share of interior and exterior house painting and dabbled in automotive painting, and I’m keenly aware that paint changes color as it dries. This usually isn’t a problem when you’re painting a large surface, such as a wall, but it can give you headaches when you’re touching up an existing paint job.

In general, paint tends to darken as it dries, but in my observations, the effect varies according to several factors, including:

• Type of paint you’re using
• paint sheen
• qualities of the surface you’re painting
• amount and quality of ambient lighting

Your eyes can deceive you into thinking a paint color is darker than you expect when you spread it on a surface that is surrounded by other colors. But subjective impressions aside, paint really does darken– and the reason has to do with the drying process itself. This post will explain how this happens and what you can do to avoid color-matching surprises.

Also, discover how to get rid of the paint smell.

Paint Components and Their Roles

All paints, even flash-drying ones like lacquer and shellac, contain the same three components in various concentrations:

• Solvents turn the paint mixture into a liquid and evaporate when you brush or spray the paint. Solvents tend to reflect light, and that’s one factor that makes the paint appear brighter when it’s a liquid than it does after it dries.
• Pigments provide the color. Most modern pigments are made from inorganic minerals that absorb light better than they reflect it. When the paint is a liquid, the pigments are dispersed in the solvent, but when the paint dries, the pigments become more concentrated and deeper in color. That’s another factor that contributes to darkening.
• Binders turn hard when exposed to the atmosphere and protect the painted surface. Solvent evaporation is the main cause of hardening, but some binders also undergo a chemical transformation (curing) after all the solvent is gone to make them even harder. The hardening and curing of the binder usually don’t have much of an effect on the final color.

In addition, some paints contain additives to control sheen, improve color uniformity and kill mold, among other things. Of these, sheen-controlling additives are the ones most likely to have a darkening effect, as they are designed to disperse light.

The Science of Drying: Evaporation vs. Oxidation

When most people talk about paint “drying,” they’re usually referring to solvent evaporation. Once all the solvent is gone, the paint is no longer tacky, and you can re-coat it…that’s what most people mean by dry. However, that’s not all there is to it, as anyone who has pressed their thumb into a supposedly dry-painted surface and left a thumbprint would know. The paint also has to harden, and it does this when the binder combines with oxygen in the air or oxidizes.

Oxidation, or curing, can take different periods of time for different paint products. Most waterborne products, including acrylic, latex and polyurethane paints, cure in a couple of days, but some oil-based products, particularly those with binders containing plant-based alkyds, can take a week or two. For those concerned about darkening, the good news is that curing doesn’t affect the final color as much as drying.

Factors Influencing Paint’s Final Shade

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While there are actual, physical reasons why paint darkens as it dries, it’s important to acknowledge the subjective ones. Painted woodwork will appear darker against a white wall than against a dark one, and it will look darker in a poorly illuminated room than in a brightly lit one. These subjective impressions are due to the way our eyes—and our brains—interpret the colors around us.

When it comes to the final color of a paint, the physical factors that influence it include the following:

• Amount of pigment: Some paints have a higher pigment-to-volume concentration (PVC) than others. Paints with a higher PVC cover better and look more vibrant, but because they contain more pigments, they darken more when they dry.
• Sheen: Paints that dry to a flat or matte sheen generally appear darker than those that dry to a gloss or semi-gloss finish. This is due to the brightening effect of a reflective, glossy finish.
• Substrate: The color of the surface before you paint it can have an effect on the color after painting. You can usually mitigate this with extra coats, but this makes the paint layer thicker and darker.
• Application method: A brush or roller leaves a subtle texture that reflects light and brightens the final shade. A sprayed finish has no texture and, therefore, appears darker.
• Additives: Additives that flatten the sheen can darken the final shade because they absorb light.

Understanding Undertones and Their Effects

When you’re painting furniture or walls, you sometimes have to mix paints of two different colors to get the color you’re after. That can produce undertones, which are a result of the varying pigment concentrations in the colors you mix to produce the final one. Undertones are subtle shades that alter the final color incrementally, and while they might not be immediately visible, they can become obvious when the lighting changes.

The best way to avoid them is to add pigments to a base color to get paint with the color you need rather than combining paints that have already been mixed.

Tips for Predicting the True Dried Color

You can’t beat paint chips for color accuracy, so if you have a stock color mixed at a paint store, dab a little of the wet paint onto the color chip and let it dry. If the mixing is accurate, the dab should pretty much disappear, and if the mixing isn’t accurate, you’ll be able to tell at a glance whether the shade is darker or lighter than expected. The key is to let the paint dry before making the comparison.

Because background color affects the final shade, it’s a good idea to do a separate test with the same material you’re going to paint. For example, you may be painting pine woodwork. Get a piece of scrap pine, seal it with varnish, paint it and check the color after it dries. Examine it in full and dim light shining at the angle it will strike the painted surface.

FAQ

Why does my paint look perfect when wet but different when dry?

Paint looks different when dry because, when the solvent evaporates, the binders and pigments coalesce into a hard crust that absorbs light better than it reflects it. The crustiness is most noticeable with matte finishes that have a high pigment concentration.

Can room lighting influence how we perceive dried paint colors?

Lighting definitely changes how we perceive dried paint color. Shades appear lighter in bright light and darker in dim light.

How many coats of paint are needed to achieve the true color?

At least two coats of paint are needed to achieve the true color. The first coat seldom provides complete coverage. When you’re painting highly textured surfaces, like stone, brick, concrete or rusty metal, you may need three coats or even more.

Are there specific paint brands that have less color variation upon drying?

The more expensive the product, the less likely it will change colors when drying. This is because expensive paints typically have a higher ratio of solids (binders and pigments) to solvent. The product’s volume solids (VS) ratio is usually found on the manufacturer’s website.

On the budget side, interior paints that combine a paint and primer typically have a higher volume solids ratio than ordinary paints. Most paint manufacturers, including Behr, Sherwin-Williams, Benjamin Moore and others, sell “paint-and-primer-in-one” products for between $30 and $40 a gallon.

Does using a primer affect the final dried paint color?

Yes. A light-colored primer will brighten the final color while a dark primer will darken it. To get as close to the true shade as possible, I sometimes tint primer with the topcoat color.

Conclusion: Navigating the Paint Drying Spectrum with Confidence

To put it all in a nutshell:

• Paint typically darkens as it dries because the solids are more concentrated after the solvent evaporates. You can minimize this effect by using a product with a high solids (and low solvent) concentration.
• The final shade is influenced by lighting, the color of the substrate and the surrounding colors. You can predict the final shade by comparing the dried paint to a color chip, but if you want more accuracy, do a color test on a sample of the material you’re painting, and examine it in different types of lighting.
• Color perception is subjective and is influenced by surrounding colors as well as lighting. To get the most accurate idea of how a final shade will appear, paint a test object, let the paint dry, and examine the object under the same lighting and next to the same colors as the surface or item you plan to paint.