We all wonder how paper turns yellow over time. Some experts attribute the process to the oxidation and degradation of optical brightening agents. However, there are many reasons why paper might turn yellow. These include lignin content, deterioration of optical brightening agents, and aging process. Read on to learn the most common reasons why paper turns yellow. So what causes it? And how to keep it from deteriorating too much?

lignin content

Paper becomes yellow over time as lignin, which is a polymer, oxidises. This change in lignin’s chemical makeup allows it to absorb light. When exposed to oxygen, it will absorb more light and turn the pages darker. Newspaper is more prone to this process because it does not undergo a chemical solvent process to dissolve lignin. Therefore, it will not yellow as quickly as white paper.

Oxidation happens when extra oxygen molecules get trapped within the polymer. These oxygen molecules break alcohol subunit bonds and create chromophores. These chromophores are what our eyes use to see color. When exposed to light for an extended period of time, the lignin becomes yellow or brown. In addition to the yellowing effect, oxidation can make the paper look dingy.

oxidation

If you’re wondering how long does paper take to turn yellow, you’re not alone. Most people are concerned about the condition of their newspapers, which can become difficult to read as the pages begin to yellow. While the process is not entirely destructive, prolonged exposure to sunlight can cause the paper to turn yellow. Listed below are the reasons why paper starts to turn yellow. Keep reading to find out more about why newspapers and other paper products are so susceptible to this condition.

Over time, lignin in paper oxidizes, giving the pages a golden yellow tinge. In addition to losing their original color, paper loses its original hue due to oxidation. The oxidation process is more accelerated in papers that contain more lignin than those with less. Moreover, some factors like weather conditions or state of preservation can speed up or slow down this process.

deterioration of optical brightening agents

Many papers used in the printing process contain optical brightening agents (OBAs). These dyes absorb ultraviolet (UV) energy and reemit it in the blue part of the visible spectrum, which makes the paper look brighter. However, when exposed to light for an extended period, these agents break down, resulting in a yellow color in the printed paper. This is the most common cause of paper turning yellow.

The degradation of OB’s causes paper to turn yellow. The degradation process is gradual and usually occurs during the early stages of foxing. Typically, OB’s are removed with water, which is effective for removing the paper’s yellow hue. Water damage does not cause paper to turn yellow, but aging causes the yellowing. This problem is a major concern, but there are solutions for it.

aging process

In a typical book, how long does it take for paper to turn yellow? The answer depends on the paper, the amount of light exposure, and the preservation methods used. Books can last for several generations and if maintained well, can last for more than one. In addition, paper can fade due to various factors, including humidity, heat, air circulation, and direct sunlight. Below are some tips to help delay yellowing.

The amount of lignin in the ingredients of paper has a direct relation to the yellowing time. Excellent-quality paper, which undergoes a thorough bleaching process, is low in lignin. On the other hand, inferior quality paper, hardcovers, and cardboard contain a greater percentage of lignin. In addition to the amount of lignin in paper, humidity is also an important factor in the weathering process. Books that are stored in conditions too dry for a long time may become damaged and brittle.