T-shirts that change color in the sunlight are extremely popular, especially in certain geographic areas. They make great souvenirs and are a fun novelty item for both children and adults alike. Many people however are simply mind boggled by the idea of a T-shirt that changes color in sunlight. A brief explanation can help you to understand it a little better.

The dye used in dying the T-shirts that change color with heat is called a thermochromic dye. Simply put, thermochromic means that a chemical change in the item causes it to change color with temperature differences. The same principle is used in mood rings, flat thermometers and other heat indicators. Such dyes when used in the fabrication of clothes results in a product which changes color if touched by a warm hand or worn outside in the sun.

In the process of dying such T-shirts there are actually two different dyes which are used. One is the color that you see when the T-shirt is hot, the permanent color. It is a regular dye, but it is covered by the temperature-sensitive dye. The change comes from a chemical reaction, caused by warmth that temporarily blocks the appearance of the thermochromic dye. The thermochromic dye is in microcapsules, which become a part of the T-shirt fabric. These microcapsules change greatly with heat to become transparent. The combination of the thermochromic dye and the permanent dye is the color you see when the tee is cool in temperature.

Such T-shirts have actually been around since the late 1980’s. Some companies that used to produce them have gone out of business because their technology simply wasn’t good enough and the shirts would get damaged easily. However, there are still companies around today, which have invested in a great amount of research and have come up with better technology and a better product.

A similar product also exists, which is a thermochromic print for regular T-shirts. Such prints are typically black and white when cold but they turn multi-colored when exposed to sunlight.  They also rely on thermochromic reactions. Such T-shirts are also very popular in certain regions and as souvenir tees.

These types of T-shirts are lots of fun, but typically do not have a long life expectancy. Therefore, investing in quality T-shirts with fun prints on them is a much better bargain for your buck. In fact, if you choose custom-made T-shirts you can have them made for every mood, every event, every day and in every color. You can opt to print something fun on them, something serious, a statement of fact, a belief, something you are proud of, something you love or a great image that you enjoy.