Secret agents of Ivan the Terrible had to write their secret reports with onion juice, which, when dried, did not leave traces on paper. Lenin, forced to resort to secret writing under conditions of secrecy, used milk. Invisible, or sympathetic, ink today can only be useful to us in a situation where we are going to surprise someone, write a secret note or have an entertaining experience with children. It is extremely easy to make invisible ink at home, there are several ways, depending on the source material.
It is necessary
Small dishes, onion or lemon, milk or sweet (salty) water, brush or fountain pen, candle or iron
Instructions
Step 1
Grate the onion on a fine grater and squeeze the juice through cheesecloth into a cup. The ink is ready. Instead of an onion, you can use a fresh apple.
Step 2
Stir sugar or salt in a little water. It is also invisible ink.
Step 3
Cut the lemon and squeeze the juice from several slices into a small container. You have received sympathetic ink.
Step 4
Pour some milk into the cup. Can be diluted with water. Either way, you will end up with developing ink.
Step 5
Now test the ink formulations obtained. To do this, take a sharpened stick, thin brush or fountain pen and, dipping it in sympathetic ink, write a few words on a piece of paper. Or draw something. Let dry. Letters or a drawing of a letter over a fire (at a distance of 10 cm) will get the same result. The secret of invisible ink is simple: some of the substances contained in lemon juice, onions, milk, sweet or salty water, when exposed to heat, break down faster than paper ignites. This chemical process gives off combustion products.
