The real issue is the same sort of force you get when you press any two extremely flat objects together, especially if they are wet. One issue is atmospheric pressure, as you try to separate the plates you are increasing volume and hence decreasing pressure, the air pressure on top of the upper surface might cause a force. Then there is the viscosity of the fluid itself, if the separation occurs beneath the surface then new fluid must flow into this space.
So the idea as suggested by Michel Jullian on the group was to remove atmospheric pressure and create a print method where the base of the vat was wetted only. I decided to do some tests and here they are: