Downloading ImarisViewer 9.9.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. This free software for Mac OS X is a product of Oxford Instruments. The program lies within Design & Photo Tools, more precisely Viewers & Editors. We recommend checking the downloaded files with any free antivirus.
From the developer:
Imaris Viewer is a free 3D/4D microscopy image viewer for viewing raw images as well as those analyzed within Imaris. You can share your beautiful images with colleagues, collaborators and even family using the same high performance Imaris rendering as you have in the lab. And you can take that high performance Imaris rendering with you wherever you go: home, conferences, sabbaticals, or any of your other exciting travels.
You may want to check out more Mac applications, such as Smith Chart for Mac, TVPaint Animation or HDR MAX, which might be related to ImarisViewer.