If you remember your science class at school then you may remember Brownian motion. The effect of 'seeing the unseen via the seen'. In other words the effects of air molecules are shown via their collisions with smoke or pollen particles suspended in air.
So using this principle to manifest unseen spirits using ink trails in en-sorcelled water seemed a distinct possiblity.
Below are examples of 'unremembered dreams' preserved in brine and rendered visible otherwise known as psychometamorphosis via the menstruum of undines...
Sweet Dreams!!
loveslifeloveschocolate
Sweet dreams? maybe.