If I save a document as a zip file using Atlantis will Atlantis reopen the file (unzip) it or do I need to open it using a zip program.
In other words will Atlantis unzip a document that has been saved using its own zip.
It is impossible to tell who created this or that ZIP.
Writing and reading ZIPs are very different procedures.
A ZIP file might contain not only documents but other files too (executables, sounds, etc).
Maybe Atlantis will allow to "open" ZIPs in the future.