Abstract: Ultraviolet colour vision is widespread in many animals. UV photography has become a powerful tool for studying colour-mediated plant–animal interactions. However, acquiring true UV images still involves technical hurdles, and the technique is often confused with UV-induced fluorescence photography, leading to misinterpretation of results. Here we introduce the biological significance of UV and fluorescence pattern, and interpret common misconceptions. We also introduce the principles, equipment configurations, and key operational steps for obtaining both UV-reflectance and fluorescence images with digital cameras. By analysing matched sets of visible-light, UV, and fluorescence images of diverse flowers, we demonstrate the fundamental differences and limited connections between the two imaging approaches. Although fluorescence and UV-reflectance images both relate to floral pigment chemistry, the relationship is complex and fluorescence images cannot substitute for UV images in quantitative analyses. We also provide a detailed hardware guide for UV photography and an affordable smartphone-based workflow, offering an accessible entry point for researchers interested in biological colour studies.

Key words: ultraviolet imaging, fluorescence imaging, pollination, evolution, floral colour, animal vision, methodological guide