Side view of the fluorescent imaging apparatus. Excitation light was provided by two blue LEDs placed at a 60° angle with respect to the camera post in order to homogeneously illuminate the sample under observation, and each equipped with an optical filter in front of it to prevent spectral overlap. An SLR camera with a 500 nm longpass filter was positioned above the sample. The entire apparatus was enclosed in a lightproof enclosure. When other excitation sources were used (UV, white light), the blue LEDs and its bandpass filters were removed, and in the case of UV LED a 400 nm shortpass filter positioned in front of the LED, and a 400 nm longpass filter in front of the SLR camera.