Gum and Stamps: Part I


Problems with Gum Toning:

Some stamp collectors have been encountering problems with toning of the gum on some of their mint stamps. Toning is a condition where the gum darkens or becomes discolored and is usually caused by excess heat or humidity, or by acid paper. The stamps of some countries have always been a little prone to gum toning, which is sometimes called tropicalization. Those countries include Italy, France and the French Colonies, Portuguese Colonies, and several African countries. Many of the stamps will tropical gum (toned gum) are from the period between World War I and World War II, and as the stamps from that period age over time, the problem may affect more and more of them.

Reports from stamp collectors that are experiencing gum toning seem to indicate that the problem mostly occurs with stamp collections that have been stored undisturbed (i.e., left alone) for long periods of time in hot and/or humid locations. The toning may be the result of excess or long-term heat and humidity, from the stamps being printed (possibly) on acid paper, or a combination of both factors.

The moral of the story? Make sure your stamps, especially your mint stamps, are always kept in a cool, dry place. And if you collect stamps from the countries and time period where toning is becoming a problem, consider collecting only used stamps.