How does blood visually appear under ultraviolet light?

Blood visibly absorbs ultraviolet (UV) light due to the presence of various components within it, such as hemoglobin. When exposed to UV light, the properties of blood enable it to absorb specific wavelengths, resulting in a darker appearance rather than reflecting or glowing. This absorption is part of why blood can sometimes be difficult to detect in the dark or under certain lighting conditions.

Understanding how blood interacts with UV light is essential for techniques used in forensic science, especially when searching for bloodstains at crime scenes or in investigations. It helps forensic technicians know what to expect when they utilize UV light as a tool for discovering biological fluids.