Invisible ink is a solution for writing on paper. Initially, the inscription cannot be seen until some chemical action is applied to the ink. There are many different recipes for invisible ink, but most of them still leave marks on the paper that can be seen with the naked eye. Today we will prepare real spy invisible ink that cannot be noticed before development.
How to make invisible ink from baking soda
To make invisible ink we need:
- water;
- spoon;
- writing utensil (toothpick or cotton swab);
- writing paper;
- candle or other heat source.
Stirring constantly, add baking soda to warm water until it stops dissolving. Dip a cotton swab into the solution, squeeze it a little to remove excess liquid and write your secret message. It's that simple!
Making invisible ink using copper sulfate
We prepare a weak, slightly blue solution of copper sulfate and write it on paper with a stick, dipping it into it. After drying, the inscription is almost invisible. To develop the inscription, you need to hold a sheet of paper over an open bottle of ammonia. When it appears, the inscription is blue-green. This is an ammonia complex of copper obtained as a result of a chemical reaction.
Ammonium Chloride Invisible Ink Recipe
We will need quite a bit (on the tip of a knife) of ammonium chloride (ammonia). Add a teaspoon of water to it. Ready! The resulting solution can be used for secret writing. Invisible ink can also be revealed using heat.
Cobalt Chloride Invisible Ink Recipe
Perhaps the most effective recipe for invisible ink includes cobalt chloride and water. What’s remarkable about it is that after drying on paper, the solution is almost invisible to the naked eye. Highly diluted cobalt chloride forms a crystalline hydrate of a pale pale pink color, which visually completely merges with the white sheet. But after heating, bright blue letters appear on the paper! However, if the paper sheet is moistened, for example, by holding it over steam, the letters will disappear again, because crystal hydrate is formed.
Using invisible ink, you can write any words and draw different pictures. But then they will disappear! Surprise your friends at a party or birthday, write a secret note to a friend, or do a fun experiment with the kids. There are many ways to make invisible ink.
Making invisible ink from lemon juice
Squeeze the juice from the cut lemon into a bowl. Add a little water and stir. Let's test our ink:
- take a sharp small stick or thin brush. It’s good if you have a pen with a feather;
- dip a stick in ink and write something on a white sheet of paper;
- let the inscription dry - the message will become invisible;
- Iron the invisible inscription on the sheet with an iron, the ink will begin to appear.
You can hold a sheet of paper over a lit candle at a distance of 10 cm - a similar result will come out. The inscription will be brown. The same dark inscription from invisible ink after heating will be obtained when using apple, onion and other juices with a high acid content.
Making invisible ink from milk
Pour a little milk into a cup. Dip the stick in milk and write something on paper. Let the milk dry well on the sheet. To read the inscription, heat the piece of paper on a light bulb, over a candle, or iron it with an iron.
Making invisible ink from starch
The ink preparation process is as follows:
- combine 2 parts starch with one part plain water;
- heat the resulting paste over low heat, stirring all the time;
- let the paste cool;
- Use a cotton swab or a sharp wooden stick to write words on paper with cooled ink.
To manifest words, lubricate the piece of paper with an aqueous solution of iodine. The paper will turn a light purple color. And the words that appear from the ink will turn dark purple.
Making invisible ink according to an ancient Chinese recipe
Ancient Chinese emperors used rice water to send secret messages. Cook thick rice porridge. Make sure that the rice does not absorb all the liquid. Use this water as invisible ink. Write a message on paper. To develop the inscription, lubricate the paper with an aqueous solution of iodine.
Making invisible ink from baking soda
Prepare:
- water;
- grape juice;
- baking soda.
Combine water and soda in a one to one ratio. Mix them well in a bowl and you have a soda-based ink. Put them on paper, but heating will not help to reveal the secret message. Use grape juice. Dip the brush into the juice and paint the paper until the inscription appears.
You can use an oven instead of an iron, candle or light bulb to heat the sheet. Place the secret message in a hot oven and wait a few minutes for the message to appear. Invisible writing appears on a sheet of paper when heated because the ink substance chars faster than the paper.
Don't forget about safety precautions if you show your message over an open fire! Prepare a saucepan with cold water in advance. In it you will extinguish the leaf if it accidentally catches fire.
Choose any ink recipe and surprise your friends or play spy. Even the secret agents of Ivan the Terrible wrote their messages to the Tsar with onion juice, and no outsider could read the message.
Sympathetic ink is a solution for writing information on paper. They differ from ordinary ink in that the message written with them cannot be seen until certain conditions are applied, be it heat, light, etc. This method of transmitting information has been one of the main elements of encryption at all times. As a rule, secret information was first written on a blank sheet of paper using sympathetic ink. After drying, a regular message was applied on top of the transparent inscription using simple visible ink. Such letters, as a rule, were heated to create a secret code, and then the sheet was destroyed. There are many different recipes for invisible ink, including purely chemical ones, which are sold in ready-made form today in office supply departments. However, you can prepare such spy ink yourself.
To do this you will need: Regular baking soda, some warm water, a spoon, a toothpick with cotton wool (you can also use a cotton swab or a refillable fountain pen), a sheet of paper and a candle.
Step 1. Baking soda must be diluted in water to form a concentrated solution. Allow the mixture to cool slightly. It is not necessary to ensure complete dissolution of the soda.
Step 2. If you have a fountain pen, you can fill it with freshly prepared solution.
Then we use it. If you don’t have such a device at hand, you can use a cotton swab or a regular toothpick with a piece of cotton wool at the end.
It is necessary to dip it in an aqueous solution of soda and squeeze it lightly. After this, you can safely write a message on a blank sheet of paper.
Step 3. It is advisable to let the ink dry a little before starting to develop the letter. In order for the secret record to become visible, the sheet with it must be held over heat. It could be an iron, gas or electric stove, but in our case we used an ordinary candle. To prevent the paper from catching fire, you need to move it lightly over the flame.
Step 4. If everything is done correctly, then after about 30-40 seconds a yellow-brownish inscription will appear. Ready! The inscription is revealed. You can also heat a sheet with a secret recording on a battery, but this will take much longer, and the recording itself will not be as bright.
You can also use lemon juice or concentrated vinegar instead of soda solution, however, these substances leave slightly visible marks on the paper, which no longer corresponds to the “secret” stamp.
Writing with sympathetic or, as they are also called, invisible ink is initially invisible to the naked eye. To make them visible, you need to apply a certain chemical effect to invisible ink. This could be heat, some kind of chemical developer, or even special lighting.
The history of invisible ink goes back to ancient times. The famous ancient Roman poet Ovid pointed out the possibility of writing with milk, in which case the written material appears when heated. The ancient Greek philosopher Philo of Alexandria gave an example of a recipe for invisible ink back in the 1st century. In his recipe, they were made from the juice of ink nuts (cecidia). Ink nuts are growths on plant leaves caused by insects or fungus. In his case, the letters appeared after the writing was exposed to a solution of iron-copper salt. Both in the Middle Ages and in later times, there were many recipes for invisible ink, most of them are easy to reproduce at home. We all know stories about Russian revolutionaries who wrote secret information with milk between the lines of ordinary letters. True, this trick was quite well known to prison staff, so such correspondence did not bring much success.
And from historical information we will move directly to the theory of how to make invisible ink with your own hands at home.
How to make invisible ink using copper sulfate
A dilute solution of copper sulfate (CuSO 4 x 5H 2 O) has a pale blue color. Using this solution it is easy to make invisible ink. To do this, dissolve a little copper sulfate in water. Now, using a stick or a match, you can write something on plain paper. And in order for what is written to appear, you need to hold the paper over ammonia. The ammonia vapor will react and bright blue letters will appear on the paper (a complex compound of copper ammonia is formed).
Invisible ink according to an ancient Chinese recipe
In ancient times, Chinese emperors used rice water to write secret letters. After drying, the rice water leaves no visible marks on the paper. To develop what you have written, prepare a weak iodine solution and moisten the letter with it. Blue letters will appear. This is because starch (and rice water contains a lot of starch) becomes visible when it reacts with iodine.
How to Make Invisible Ink Using Lemon Juice
Dip a stick in lemon juice and write something on the paper. Citric acid (and lemon juice is actually an acid) darkens when exposed to temperature, so it is enough to heat the paper a little (over a lamp or by ironing it) for the writing to appear.
DIY disappearing ink using iodine
Finally, we’ll tell you about another equally important spy attribute - disappearing ink! With the help of disappearing ink, you can write or draw anything, but under special influence the inscription will disappear beyond the possibility of recovery! Vanishing ink can be prepared by mixing 50 ml of alcohol tincture of iodine with a teaspoon of dextrin (how to make it at home is described in the article). Filter the precipitate and write or draw on plain paper with a clean solution. The inscription will disappear in a couple of days. This is due to the volatilization of iodine.
A variety of substances can be used as sympathetic ink:
List of substances with which you can make invisible ink with your own hands at home
- Wax - tooth powder developer
- Milk - appears when heated;
- Apple juice - appears when heated;
- Onion juice - appears when heated;
- Rutabaga juice - appears when heated;
- Washing powder (with bleach) - appears under ultraviolet light;
- Starch - manifests itself under the influence of iodine tincture;
- Aspirin - manifests itself under the influence of iron salts
Now you know how to make invisible ink with your own hands at home. Try at least one of the above recipes and play spy with your child!
CategoriesMaking invisible ink today is not difficult at home. And if the revolutionaries were forced to write with them for the purpose of conspiracy, and the agents of Ivan the Terrible - out of fear for their lives, today they are needed, at best, to stage an innocent joke designed to entertain a despondent company, or to conduct an entertaining chemistry experiment for children. Moreover, there are many ways to make this amazing writing aid, and the ingredients for it can be found in every home.
Making invisible ink at home: five ways to make it
You can try to make five versions of sympathetic ink, test them and decide which of them have the greatest “spy” qualities.
So, we need:
- Shallow bowl;
- Onion or apple;
- Lemon;
- Milk;
- Sweet or salty water;
- Brushes or fountain pens;
- Iron or candle.
Excellent ink is made from milk: simply pour some milk diluted with water into a bowl, take a fountain pen and write something on paper. Gently heating the sheet with an iron will reveal the characters you have written. By the way, Vladimir Lenin, fleeing the persecution of the gendarmes, wrote his messages to the party with milk.
You can grate the onion on a fine grater until it becomes a paste. Then squeeze the resulting juice through a piece of gauze into a bowl. The acid contained in onions is the ink. By the way, a fresh apple can be a complete substitute for an onion.
Lemon makes perhaps the most effective ink. You just need to cut the fruit and squeeze the juice from several slices into a bowl. By the way, you can write with such invisible ink even with cotton swabs.
However, you can do without lemon: 100-150 ml. Dissolve sugar or salt in warm water. The effect of writing with such ink is less pronounced, but this is perhaps the easiest way to surprise guests with secret letters:
Homemade invisible ink is worth trying. To do this, write something on a piece of paper, preferably white, thick and of good quality. You can write with a pointed stick, a match, a thin brush or a fountain pen, just a few characters are enough. Next you need to let the writing dry. Gently iron the design with an iron or hold it over an open fire, such as a candle, and the writing will appear.
The secret of sympathetic ink is easy to discover: its composition includes some substances (acids) that, under the influence of heat, disintegrate faster than the process of burning the paper begins. We see traces of this decay on a sheet of paper.
Let's look at several popular chemical ink recipes
Preparing invisible ink from “inedible” things is a little more difficult and slightly longer, but the scope of such ink and the effect of writing with it are much wider.
So, to make ink we will need:
- Potato
- 100-150 gr. ethyl alcohol
- Small amount of nigrosine
- Sodium tetraborate
- Tincture of iodine
- Washing powder
- Copper sulfate solution
Let's start with the simplest ways to make ink
We dissolve baking soda with water in a ratio of 1 to 1. Letters made from soda appear on paper literally 10-12 minutes after writing by heating the sheet.
It is not difficult to make spy ink from ordinary washing powder. Dilute a little powder in water and use a cotton swab to write something on a piece of paper. The inscription becomes readable if it is placed under an ultraviolet radiation source.
The next recipe is more complicated, but the effect is worth trying: put rosin and nigrosin in proportions of 50 g in a glass container. Pour 350 ml of the substances. ethyl alcohol, mix well. The container must be tightly closed to prevent ethanol from evaporating.
Another option: 100 gr. Combine borax with half a liter of water and mix thoroughly.
By combining the third and fourth recipes, we get the original fifth. For the best effect of using this ink, the solutions must be thoroughly mixed after mixing.
An interesting effect is produced by ink that disappears over time. You need to pour 25-30 grams. dextrin into a small glass container and pour 60-70 grams there. solution of iodine and alcohol. At the end of the process, mix the resulting solution thoroughly and separate the precipitate. If a letter is written in such ink, it will “disappear” within 24 hours.
Video on the topic of the article
You can make homemade invisible ink yourself in literally 5-6 minutes if you carefully study the proposed selection of videos. If you are planning to make cute ink with your child, be sure to watch the episode of the animated series “The Fixies” dedicated to this chemical trick: it will be useful and educational for him!