Wash the plate one last time in water to remove the fixing agent, then dry.
To protect the delicate image, apply a coat of varnish to the plate. Application is conducted in much the same way that the collodion was applied to the plate.
First, heat the bottle that contains the varnish over a flame. Also heat the glass plate over a flame. When both are blood warm, pour the varnish onto the emulsion side of the plate, tilt the plate until it is fully covered, then pour the excess back into the bottle.
On the glass plate is a visible negative image. There is a dark coating of silver where light has struck the plate; the plate is clear where it was not exposed to light.