This workflow for KNIME is used in the article "Pyrite formation from FeS and H2S is mediated through a novel microbial redox activity" by Joana Thiel, James Byrne, Andreas Kappler, Bernhard Schink & Michael Pester (https://doi.org/10.1073/pnas.1814412116) to count DAPI stained bacterial cells on filter material in fluorescence microscopy images. The workflow was designed by Stefan Helfrich.