Furniture can change colour over time. Do you know why?

From what I've seen since I started writing about furniture refinishing, there are a lot of people who appreciate old furniture. There are also many who, if they don't have old furniture, prefer to buy furniture that is made from scratch to look like old furniture, to have that look and the traces of the passage of time. And yet, not all the effects of this passage of time on furniture please us, or at least, not all of us. Sometimes the marks appear much too quickly and that really can't please us. But why does this happen, what factors cause the original appearance to change?

Like everything else on this earth, furniture ages. It ages wood, varnish, glue, etc. Sometimes the process is faster, sometimes slower, depending on the type of wood and the quality of the materials used. Environmental factors such as temperature, humidity, solar radiation, etc. determine ageing. The ageing of furniture is determined by the resistance of the wood and finishing materials to these factors.

As we know, wood changes colour over time. A piece of wood left out in the sun, battered by rain and wind, changes colour to grey in a few months. But if it is protected with varnish, the fading is slowed down. The same happens to wood indoors. Even if it's not as aggressive as outside, solar radiation coming through the window can change the colour of the wood.

Even artificial light can do that. Over time, light-coloured wood will darken (pine, molid) and the dark one will fade (nucThere are also species of wood that are more sensitive and whose colour begins to change as soon as they are cut. The best example of this is cherry.

To avoid rapid colour change and delay natural ageing as long as possible, the following can be used various finishing materials. The simple use of a first layer of berry will make the wood not change colour so much. A natural piece of furniture will change colour faster than a coloured one, even if the colour is light. You can also use varnishes that are specially made to protect, which have UV filters in their composition. A yellowing-resistant varnish is acrylic on solvent. It also protects chemically discoloured wood. The better the protection, the better the whole system (primer and varnish) is used, not just the final varnish coat.

Varnishes also contribute to the ageing of furniture. In general, varnishes yellow over time, which gives that old look. The degree to which varnishes yellow depends on their nature. For example, nitrocellulose lake is one of the lakes that yellow quite quickly and quite visibly. The resin contained in the lake comes from cellulose, a component of wood, and is therefore also subject to colour change. The yellowing of nitro varnish can be reduced a little by using products with UV filters, but the varnish will still yellow. The same goes for alkyd, oil-based paints. They too yellow over time no matter how treated they are.

Another type of varnish that yellows over time is polyurethane varnish. Here, a decisive role is played by the catalyst, which is very sensitive to yellowing. The choice of materials is particularly important when the furniture produced is white. In this case you should make sure that you use products with a high resistance to yellowing. Otherwise the furniture will yellow quite quickly (less than 1 year) and the process will be accelerated by high temperature or aggressive factors (steam, abrasive materials, etc.).

How the materials are chosen and how the furniture is finished are also very important for how the furniture will look over time, not just when you buy it. Some products are more durable and better, and using them will make your furniture last longer. However, this comes with higher costs and therefore a higher price you have to pay for your furniture. But, I assure you, it's worth it!