Figure 3
The Vitrobot Mk IV `blot-force' steps are 25 µm offsets of the blot pads. The optimal blot force (and blot-pad separation) to obtain a wedge across the grid containing most ice thicknesses is when the blot pads (without filter paper) are just touching or letting a sliver of light through (indicated by the arrow and rectangle). Fine tuning can then be performed by taking full atlases of grids frozen with ±1 or 2 blot-force steps. Increasing the blot force moves the blot pads closer together and therefore the wedge higher (less thick ice areas). Decreasing the blot force moves the blot pads apart and therefore the wedge down (more thick ice areas). |