Hi Raider007,
In Item Master, we can plot files attached to the items or all files associated with the entire item BOM structure. So when we plot using visualization files, the files' responding visualization files will be plot. watermark can only be seen in the Item master's view tab, not in vault explorer's view tab, but we choose the latter, so you see the files without watermark.
You can do setting in "Plot Options" dialog, or click Print button above the view in the view tab.