Does Sunlight Darken Wood? All You Need To Know!

does sunlight darken wood

Sunlight is considered one of the main environmental elements that affect the lifetime of wooden furniture and woodworks. Both indoor and outdoor wooden furniture get hit by sunlight and that changes their physical and chemical structures dramatically over time. when it comes to physical appearance, I was always wondered Does sunlight darken wood?

I looked into it and here’s what I discovered:

Yes, Sunlight darken the wood. Wood is photosensitive and changes with sunlight. Exposure to the UV (ultraviolet light) in sunlight causes the darkening of the wood over time. Wooden furniture that is directly exposed to the sunlight change color quickly. But some dark woods tend to be lightened and Lightwoods tend to be darkened with UV exposure.

But there’s a lot more we need to learn about how sunlight affects the wood color over time.

So, in this article, I’ll dig into how does sunlight darkens the wood, what happens when you leave the wood in the sun, what wood changes color in the sun, does stained wood darken over time and many other frequently asked questions as well.

Just keep reading to learn more!

What Does Sunlight Do to Wood?

Sunlight cause to damage the wood and change its color over time. If the wood is unfinished or hasn’t applied any coatings the sun damage happens quickly than finished wood. But even though your wood is coated, without regular maintenance it will easily get damaged due to exposure to direct sunlight over a long period of time.

As an experienced woodworker, I have noticed that the time that takes for the darkening of the wood over sunlight changes because of the following factors. They are,

  • Wood Type – Wood species is a large factor and not all woods behave the same under sunlight. Some woods darken faster, and some aren’t.
  • Amount of exposure to the sunlight – If the amount of sunlight exposed to the wood is high, the wood will darken faster than the woods exposed lower amount of sunlight. Also, if the UV light in sunlight is less, the darkening process will happen slowly. Because UV light is the main ingredient in the sunlight that darkens the wood.
  • Status of the wood – Darkening of the wood over sunlight varies because being hardwood, closer to the heartwood or bark, softwood, old, fresh, finished, or unfinished likewise. 

What Happens When You Leave Wood in The Sun?

When you leave your loving furniture or woodworks in the sun, nothing happens at the beginning. But when you continuously leave the wood in the sun or if the wooden furniture is regularly left outside over time, you will notice a color change of the wood drastically.

When you leave the wood in the sun, the light color wood tends to be darkened over time and dark color wood tends to lighten over time. This happens due to chemical changes that happen inside of the wood because of sunlight.

Generally, most of the wood loses color because of sunlight. Wood is photosensitive and when it is exposed to sunlight the reactions happen. If you keep unfinished wood in the sun I will darken it faster than the finished wood because the amount of sun radiations hitting the unfinished wood is higher and start discoloration quickly.

Why Does Wood Change Color in The Sun?

UV light in the sunlight darkens the wood by accelerating the oxidation process inside the wood. Oxidation processes hold molecules together by building chemical bonds between them. Also, UV light tends to react with aromatic materials inside the wood which gives the color to the wood and change their chemical composition. This will lead to the breakdown of aromatics, and they’ll react with oxygen. The resulting oxides will further interact and degrade in the end. The bonds built between molecules will absorb and reflect spectra to form different molecules.

The light that reflects because of these chemical reactions are different than the original color of the wood. This light is known as the color that appeared when you leave the wood in the sun over time. This is how the discoloration happens and this is how sunlight darken the wood.

What Wood Changes Color in The Sun?

Literally, all the wood changes color in the sun. The amount of color changing is the only difference between them. Some wood turns darker in the sun, and some turn lighter.

So, hereby I have listed the most popular wood types and how they change color in the sun by leaving them under sunlight for at least a year.

Wood TypeColor Change in The Sunlight
Cherry WoodDarken in the sunlight
MahoganyDarken in the sunlight
TigerwoodDarken in the sunlight
PoplarDarken in the sunlight
PurpleheartDarken in the sunlight
MapleDarken in the sunlight
Red OakLighten in the sunlight
HickoryLighten in the sunlight
WalnutLighten in the sunlight

As you can all the wood types that we commonly used for making furniture and woodworks change color in the sun. Some change quickly and some take time. However, at the end of the day, each one changes because of sunlight.

Some type of off sunlight enhance their appearance and they look more aesthetic after keeping under sunlight for a while. For example, cheery wood gets a rich dark tone from having a light pale color tone after keeping it in sunlight and that’s become better in color than it used to be. Similarly, mahogany will also turn into a nice-looking reddish-brown color tone in the sunlight. Because of those reasons some people purposely keep their furniture and woodworks in the sun for a while until it reaches a noticeable color change they wish.

As a rule of thumb, darker wood tends to be lightened over time and lighter wood tends to be darkened overtime under sunlight. Direct sunlight accelerates the process.

Read: Does Walnut Wood Lighten Over time and how? All you wanted to know!

Now we have a clear idea about how raw wood/ timber changes color in the sunlight. This same effect affects the furniture that you make from those wood. I have noticed outdoor furniture turns darker or lighter over time faster than indoor furniture due to direct and indirect sunlight exposure levels.

So, let’s have a look at how stained wood changes color after keeping them under sunlight for a long period of time.

Does Stained Wood Changes Color in The Sun?

Same as unstained wood, stained wood also changes color over time when exposed to sunlight for a while. The wet fresh look of stained wood will be gone under sunlight and result in a thicker finish. This is because the dye color of stain cote will fade away under sunlight and the pigment layer will remain the same and suspended on top of the wood and give a thick dark color which is completely different from the original color of the stained wood.

How To Stop Wood from Darkening?

We can stop the wood from darkening by using sunblock to prevent our loving furniture or woodwork from exposing to the sunlight and its UV light. Sunblock prevents damage from the sunlight and makes your wood protected. But you need to make sure the wood is maintained regularly and reapply the sunblock from time to time. Otherwise, the sunblock will eventually go away under direct sunlight and wood will start to darken slowly.

Here are the things you can follow to stop wood from darkening. They are,

  • Apply finishes with UV inhibitors
  • Avoid placing wooden furniture to direct sunlight
  • Change the placement
  • Window covering
  • Awning
  • Use low emissivity glass windows

Above solutions, you need to follow before your furniture gets darkened in the sunlight. To follow the above steps, you can take actions like the given below.

Apply Finishes with UV Inhibitors

By applying finishers that contain UV inhibitors, they’ll prevent UV rays from getting into the wooden surface. They have anti UV agents to block the UV light in the sunlight.

The best finishes in the market with UV inhibitors are Lacquer and Linseed oil. Applying lacquer is fast and easy when compared to linseed oil. It dries faster and the application is also so much easier. Two coats of lacquer and linseed oil do the same job perfectly.

Even though linseed oil takes a much longer time than lacquer to dry completely, it not only gives sun protection but also protects the wood from water and moisture as well. So in terms of protection linseed oil is better than lacquer. I highly recommend both to stop wood from darkening.

Avoid Placing Wooden Furniture to Direct Sunlight

By avoiding the placement of the furniture in direct sunlight, you’ll be clearly able to decrease its darkening. This only slows down the rate of darkening. Even though you place the wooden furniture in places there is no direct sunlight, the indirect sunlight will also do the job during the daytime. But much slower than placing wood in direct sunlight.

Change the Placement

By rearranging the placement of your woodworks from time to time not only it will slow down the darkening of the wood due to sunlight, but also stop the wood from looking weird with dark and light patches all over the surface which happens due to hitting sunlight unevenly all over the surface over time.

This will equalize UV radiation exposure to the wood and spread out darkening or fading evenly by giving a constant color all over the wood.

Window Coverings

By applying window coverings you’ll be able to stop hitting harmful UV light inside your house. If you have hardwood floors that you don’t like to be darkened over time, window coverings are the best option.

The multi-layers of window coverings block the UV light and stop the wood from darkening.

Awnings

Awnings protect your house from reaching direct sunlight. No UV rays can hit the household furniture because of awnings. It not only gives good protection to the furniture from darkening but also enhances the appearance of the house as well.

Use Low Emissivity Glass Windows

Low emissivity glass windows which are also known as low E glass helps to prevent your furniture from hitting UV and IR light in the sunlight.

Unfortunately, this option is expensive. But it does the job perfectly. Coatings in low emissivity glass windows limit the UV and IR radiations getting inside the house to keep them away from darkening.

So, that’s it, guys. Hope I have covered all you wanted to know about how does sunlight darken the wood.

Did I cover all you wanted to know about: Does Sunlight Darken Wood?

In this post, we looked at does sunlight darken wood and why does it happen. Furthermore, we have discussed what wood changes color in the sun and why do some wood fades and bleach out but some darkens after keeping under sunlight for a while.

As a woodworker, my suggestion is to never leave your woodwork or furniture unfinished. With proper finishing, you’ll be able to stop the wood from darkening and keep the tone of the wood originally and freshly looked over years with proper maintenance.

Hope you’ve learned lots of new things about how sunlight affects the color of your wooden furniture. So let’s apply things we learned to your nice-looking furniture and woodworks to keep them away from darkening. Let’s give it a try!

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