Lucky discovery
if objFolderItem
is Nothing when you call
objFolder.GetDetailsOf(objFolderItem, i)
the string returned is the name of the property, rather than its (undefined) value
e.g. when i=3
it returns "Date modified"
Doing it for all 288 values of I makes it clear why most cause it to return blank for most filetypes
e.g i=175
is "Horizontal resolution"