A Study of Various Factors Affecting Stamp Identification
Chi-Ming Pang, Janesse W.S. Hui, Chi-Keung Li · Journal of the American Society of Questioned Document Examiners · 2014
Stamp identification is performed by matching unique defects present on the stamp face to those on the impressions. Unique defects are usually introduced onto the stamp face through wear, tear, and day-to-day usage. Defects can also be introduced at the manufacturing stage. However, depending on the cause, these can be either unique to an individual stamp or apparent in all stamps produced using that particular mold. In addition to defects, other essential factors that should be considered when undertaking a stamp examination are explored in this paper. These include: stamp shrinkage rates during normal use and how these rates are affected by changes in temperature and humidity, the effects of stamp re-inking, the effect of sunlight on the appearance of stamp impressions, the possibility of a duplicate stamp being used to make a questioned impression, and the “smudging” effect. The paper also discusses the significance these factors should be given when formulating opinions.