This presentation was sold out and went very well. The preparation was done completely open source:
Kubuntu 19.10
Rawtherapee 5.8 for converting the Nikon raw files
Gimp for touch up
Hugin for aligning old photos from magazines to the new scans using a slow fade
LibreOffice Impress for putting together the slide show and saving to Powerpoint .pptx format for the AV system at the museum. No issues at all with compatibility.
Many thanks to this community and the software developers.
