If you are in early chapters and have researched and built the Magic Academy, I suggest crafting. Each recipe 'offers' varying amount of Vision Vapor...
Feel free to look up Magic Academy in the Elvenar wiki if you needs details on this building
As far as I know you can't get Vision Vapor in the Spire, only from crafting items in the MA. In the Spire you can only get Spell Fragments but that's for another quest.