# Generate bleach corrected correlation functions using FluctuationAnalyzer 4G
The [Fluctuation Analyzer 4G](https://www.embl.de/~wachsmut/downloads.html)(FA) is a software tool for the interactive as well as automated processing of fluorescence auto- and cross-correlation spectroscopy (FCS/FCCS) data. It can read raw data, i.e., one-or two-channel photon streams, from various commercial suppliers of FCS/FCCS data acquisition equipment, organize such data in processing sessions by file-based management, calculate temporal auto- and cross-correlation functions, correct for photobleaching, cross-talk, and background signal and fit the data with appropriate model functions before saving the results. Refer to the manual of FA and the original article [Wachsmuth et al. (2015)](http://europepmc.org/abstract/MED/25774713) for details.