All you need to do is save the "pca_band_contrib" file to the "save_add" subfolder of the ENVI installation, then edit the "envi.men" ASCII text file. There is a website that describes how to install user functions that describes these steps in more detail : http://www.rsinc.com/serv...echtip.asp?ttid=2756 You may also want to read the Tech Tip website associated with this user contribution : http://www.rsinc.com/serv...echtip.asp?ttid=2807 - AO