Invisible ink at home: the most interesting recipes

Using invisible (cute) ink is not only an integral part of children's spy games, but also an original way to surprise friends at a party or propose to your girlfriend. It is very easy to prepare them at home, and they contain the most common ingredients that are found in any home.

Usually, to effectively display such ink, a secret message is first written on paper, and another message is written on top in the usual way. This is how encrypted information was transmitted back in ancient times.

There are several types of sympathetic ink; they are distinguished not only by their composition, but also by the conditions under which the ink becomes visible.

Invisible ink at home using lemon

The recipe for invisible ink made from citric acid is one of the simplest and easiest to prepare. All you need is half a lemon or liquid citric acid, water, a deep plate, a brush and a sheet of white paper.

• First you need to squeeze the juice from the lemon into a deep plate and add a small amount of water. In principle, it is not necessary to dilute the lemon juice, but then the ink will initially be slightly visible on the paper.
• Mix the contents of the dishes.
• Wet the brush with the resulting liquid and write your message on white paper.
• Wait until the liquid is completely dry.
• When the time comes to read the message, the piece of paper must be heated. A table lamp, iron, candle or oven is suitable for this.

Due to the fact that lemon juice has the ability to oxidize when heated, it will change color to brown. Ink prepared without lemon, but, for example, from onion juice or honey, will work on the same principle.

Manifestation Methods

To manifest a secret message, various methods are used:

The best homemade sympathetic inks are those made from soda because they are easy to make, odorless and have a long shelf life. At the same time, they dry much faster, are invisible on a sheet of paper and appear brighter.

Invisible ink made from soda

There are several options for making invisible ink from soda, but all of them are simple to implement.

For the first recipe you will need baking soda, warm water, a piece of paper and a cotton swab or brush.

• Mix baking soda and water in a 1:1 ratio.
• Stir until the soda dissolves.
• Soak a cotton swab in the resulting liquid and write a secret message on the paper.
• Wait until the inscription is completely dry.
• To demonstrate your message, you need to heat the piece of paper using a lamp or any other method. However, do not forget about safety precautions when working with heating elements so that the paper does not ignite. You should prepare a container with plain water in advance to extinguish the burning paper if the process does not go according to plan.

The second type of invisible ink recipe using soda involves using grape juice to reveal the code. After applying the ink to the paper and drying it, you do not need to heat the sheet of paper to develop the message. Simply dip a brush or cotton swab in grape juice and paint the paper until the symbols appear. This occurs due to the chemical reaction of soda and grape juice.

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 How to make dextrin with your own hands). 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! Categories FUN CHEMISTRY

Master classes

To create cute ink with your kids, it's best to stick to reliable and safe options using common ingredients like lemon juice, soda, and milk.

From soda

There are two ways to make invisible ink at home, both using baking soda. A quick chemical experiment will take no more than 5 minutes. The procedure can be performed on children over 8-10 years old.

Before creating a mascara, you need to prepare the necessary materials in advance:

• paper;
• tablespoon;
• cotton swab (can be replaced with a toothpick, one edge of which should be wrapped with a cotton swab);
• drink;
• a candle (if you don’t have one, you can use a regular table lamp or an iron to reveal the hidden inscription);
• hot water.

Instead of a cotton swab, a fountain pen is suitable, which should be filled with prepared soda liquid before applying the inscription.

When all the ingredients are ready, you can move on to the ink creation stage:

1. Make a concentrated soda solution by mixing hot water with baking soda in the same volume. Mix the composition thoroughly; there is no need to wait for the final dissolution of the loose powder.
2. Dip a cotton swab or toothpick into the prepared solution and attach a certain disk to the sheet.
3. Dry the paper well, as soda ink leaves wet fingerprints. To dry in winter, you can use a radiator or place the paper on the windowsill in direct sunlight if it is hot outside.
4. Once the paper is completely dry, you can develop it. Hold the sheet over a lit candle or gas stove.

The developing phase must be controlled because the paper may catch fire if held motionless over an open flame. In this regard, it is recommended to slowly move the sheet towards the fire. You can also develop the inscription using an iron, which is heated to the minimum temperature setting. The device must pass over the surface of the paper on which the text is located. At the end of the procedure, a yellow-brown inscription should appear.

The second method of creating sympathetic ink involves similar creation instructions, but instead of using the heating method for development, it uses grape juice. This option for creating ink is suitable for classes with young children, who are not recommended to show the procedure of heating a sheet of paper with a burning candle or lighting a fire on a gas stove.

To reveal the hidden text, you need to go over it with a brush pre-soaked in juice. During the interaction of the two components, a chemical reaction begins, which contributes to the development of the inscription, as a result it becomes visible.

Helpful tips when working with soda ink:

• It is not recommended to use halogen light bulbs, as they cause the paper to ignite;
• regular grape juice can be replaced with a concentrate so that the change in shade is more noticeable and rich;
• a weaker solution of soda can be prepared if 1 part of the loose powder is dissolved in 2 parts of liquid (the end result will remain the same).

From lemon

You can make cute ink at home using freshly squeezed lemon juice. This allows you to make the ink invisible without the use of technically complex equipment and special tools.

To conduct a simple experiment, you need to prepare the following materials:

• 1/2 part lemon;
• white sheet of paper;
• cotton swab;
• water;
• capacity;
• floor lamp;
• tablespoon.

Step-by-step instructions for making simple and cute ink from citrus juice:

1. Squeeze the juice from half the lemon pulp into a container. Add a few drops of plain water to the citrus liquid.
2. Mix 2 liquids with a spoon.
3. Dip a cotton pad into the solution and write the text on a white sheet of paper.
4. Wait until the sap dries completely until it becomes completely invisible.
5. To reveal a hidden message, heat a piece of paper by holding it very close to a burning lamp.

Freshly squeezed lemon juice is considered an organic substance that can oxidize and turn brown when heated. In order for the lettering to completely disappear from the surface when applying the finished solution to a sheet of paper, the citrus liquid must be diluted with water. Until the paper is heated, the message will be invisible.

A similar principle of action is typical for wine with vinegar, onion juice, milk, honey and orange liquid. If you are interested in how to make sympathetic ink yourself at home using other methods, you need to try various chemical experiments and take a closer look at concentrated liquid solutions under ultraviolet light.

From milk

You can make invisible ink at home from a food product - milk.

To complete the procedure, you must complete the following step-by-step steps:

1. Pour a small amount of milk into the glass, dropping the brush into the container.
2. Apply the text to a piece of paper and wait until it dries completely.
3. It is not recommended to dry paper in direct sunlight.

To reveal the hidden message, the text must be well heated. To do this, you can use a candle, a hot iron or a lamp.

From citric acid

You can make invisible ink at home using citric acid. The product is considered a simple and inexpensive raw material for conducting experiments with a child.

To prepare sympathetic ink, you need to prepare the following materials:

• white sheet of paper;
• water;
• deep bowl;
• brush;
• liquid citric acid.

Step-by-step instructions for making invisible mascara:

1. Pour liquid citric acid into a deep container and add a little water. The acid does not need to be diluted with liquid, but the ink will initially be slightly visible on the surface of the sheet.
2. Mix the prepared mixture thoroughly.
3. Dip your brush into the solution and paint the text onto a piece of paper.
4. Wait until the solution is completely dry.
5. To read the hidden text, warm the sheet with an oven, candle, iron or table lamp.

Citric acid, like citrus juice, can oxidize when exposed to high temperatures, turning brown. Above were presented the most affordable options for making invisible ink. Such experiments at home help to activate a child’s cognitive activity, awakening his interest in chemistry. However, it is considered a good way to attract colleagues and make spy games fun.

Method #1: Acid Ink (Lemon Juice)

In theory, the most tried and true method for making homemade invisible ink is to simply apply pure lemon juice (or, as mentioned, a variety of other acids) to a piece of paper. Once the paper is completely dry, you apply heat and voila! — “mascara” became visible. The acid is well absorbed into the fibrous material of the paper, leaving invisible marks there as it changes the structure of the paper fibers; When heated, areas treated with acid turn brown.

This is by far the most common method you'll see when searching online for ways to create invisible ink. However, not all so simple. As a blogger who decided to make invisible ink for his 4-year-old son describes the experiment, using citric acid as ink did not allow him to achieve the “spy effect.” Thus, according to him, when lemon juice and a small brush were used to apply inscriptions on paper, subsequently, when heated, the inscriptions did not appear. In addition, he writes that he tried various heating methods, but was unable to develop the writing made with lemon juice. For heating, a hairdryer, an incandescent lamp and even a gas stove were used, on which the blogger held a sheet of paper.

To make matters worse, the ink didn't show up with a little heat. However, with strong warming, a hidden inscription began to appear. But then the paper practically began to burn. Overall, this experiment showed that when using citric acid as a latent ink, the paper would have to be very carefully heated for a long time to develop it.

Many people on the Internet write that this method works if you hold the paper with ink hidden over a hot light bulb for 20 minutes. According to the blogger, this method is more suitable for adults rather than children, since it involves a heating source that is unsafe for children.

So father and son were disappointed with their first experiment. Then they started searching the Internet again for a way to create invisible ink. As a result, we found an interesting method, which, as it turned out, works 100%.

Making invisible ink from lemon juice

Squeeze the juice from the sliced ​​lemon into a bowl. Add some water and stir. Let's try our mascaras:

• take a sharp stick or thin brush. It's okay if you have a pen with a nib;
• dip the stick in ink and write something on a blank 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 - you will get a similar result. The inscription will be brown. The same dark inscription in invisible ink after heating will be obtained when using apples, onions and other juices with a high acid content.

From juice

Lemon juice is completely invisible on paper

Try writing on plain paper with lemon juice. The ink becomes visible after interacting with an aqueous solution of iodine. To do this, you should use a cotton swab - iodine reacts with the starch present in the paper and gives it a light purple color. The inscription on the juice remains light.

Another way to show what you have written with lemon juice is to heat the paper on a light bulb, over a candle, and iron it. The letters will turn brown.

Onion, apple and any other juice with high acidity have properties close to high temperatures.

How to make invisible fluorescent ink at home

Good fluorescent inks can be used with regular laundry detergent containing optical brighteners. After diluting the powder with a small amount of water, you can begin writing a secret message. The dried solution will not leave fingerprints on the paper, but will look good under an ultraviolet lamp.

Also sold separately. Typically, they are used to add whiteness with a bluish tint to clothing, textiles and paper intended for printing on a printer. The powder can also be used to create beautiful inks. This ink will show up on all types of paper.

Another way to make invisible ink is to use aspirin and denatured alcohol tablets. Dissolve 2-3 aspirin tablets in a small amount of alcohol. If a precipitate remains during dissolution, the liquid must be filtered. After this, you can start writing in secret. This ink does not glow on all types of paper, and this method does not work if you are writing on printer paper.

You can also use the following preparations to prepare ink, which you can try to get at the pharmacy:

You can also use sodium fluorescein, but its natural color may stand out on white paper once applied, so this ink is not invisible.

With your friends, you will probably be wondering how to make invisible mascara. There are several ways to write a secret message at home. All the methods presented below are absolutely safe and can be freely used in children's games about spies and intelligence officers.

Alizarin ink

They are also prepared with inknuts, but differ in that they contain vinegar. To prepare, you need to take 10 g of ink nuts, 6 g of copper sulfate, 1 g of gum arabic, 100 ml of vinegar. Cooking will take a long time, so immediately prepare yourself for a long process. The crushed galls are soaked in vinegar for at least 6 days. The remaining components are dissolved separately in acid. On the fifth day, you need to boil the second composition.

After both solutions are ready, they need to be drained together. Now shake the mixture vigorously. The process is almost complete. Wood acetic acid is the best solvent. Alizarin ink has a major drawback: it doesn't flow smoothly around the nib, but it leaves a thick mess on it.

Lots of options

Today, ink production is a large industry that is only gaining momentum. In Rus' they were prepared from iron sulfate, which was added to a decoction of oak nuts. Today, typical ballpoint ink is a mixture of 50 or more components. The black color is obtained thanks to dyes, but the most popular are triphenylmethane and copper phthalocyanine; they give the blue tint so popular in modern writing.

The production of ink is not complete without ferrous sulfate and tannic acids. Dyes and additives must be mixed with the solvent; they are needed to make the formula more durable. Synthetic polymers are needed to regulate surface tension.

Invisible ink

So, let's do mascara, but not simple, but invisible! Interesting? Then we prepare everything necessary.

• half a large lemon;
• water;
• tea spoon;
• soup bowl;
• cotton swab;
• paper;
• desk lamp.

After everything is prepared, let's move on to our “chemistry”. Squeeze lemon juice and add a teaspoon of water to a deep bowl. Mix lemon juice and water well and dip a cotton pad into the mixture. Now write your message on white paper, wait until the message is completely dry and completely transparent. Now comes the fun part. To read this message, you need to heat a piece of paper under a table lamp and the message will appear.

How did it work? Since the sap is a "consequence" of organic chemistry, one of its properties is to turn it brown when the temperature rises. It is then diluted with water, so that our message instantly dries up and disappears from view.

Invisible ink at home from starch

Ingredients for cooking:

A saucepan or ladle,

Aqueous solution of iodine.

1) First you need to prepare a starch paste. To do this, mix 2 parts starch and 1 part water in a ladle or saucepan. The resulting mass must be boiled slightly over low heat until warmed up, stirring thoroughly.

2) Let the pasta cool.

3) Dip the brush into the resulting ink and make a large lettering on a piece of paper.

4) Let dry.

5) To read the message, you need to stain the paper with an aqueous solution of iodine. The text will turn bright purple.

Knowing the principle of interaction between starch and iodine, this recipe can be slightly modified if there is no pure starch in the house. It is enough to prepare thick rice porridge instead of pasta, since rice contains a large amount of starch. Further steps do not differ from those described in the recipe with pure starch.

There are ready-made ink preparation kits on sale, as well as various pens filled with ready-made sympathetic ink. However, preparing them yourself using simple and affordable means will be much more fun not only for a child, but also for an adult.

Ink from gall nuts

Continuing to consider what ink is made of, we must not forget the famous discovery, namely special growths on oak leaves. They are called galls, and they contain insect larvae that produce bile. This is why the growths are called ink nuts. The juice was squeezed out of them, then mixed with iron sulfate and glue was added. The result is a long-lasting composition with a beautiful shine. Even today, the surviving manuscripts look very fresh. However, there was an important nuance. This ink was colorless; it was possible to read what was written only when the letters were dry.

Vitriol ink

Copper sulfate is sold in hardware stores, and ammonia is available at any pharmacy

To make ink from copper sulfate, you need to obtain a very weak, almost colorless solution. If you then hold a sheet of invisible text over ammonia vapor, the text will appear due to the appearance of blue-green copper ammonia. The message is displayed brightly on a piece of white paper.

You can moisten a cotton swab with ammonia and rub it over the secret inscription.

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Rice ink

Cook thick rice porridge. By the way, you can eat it, double the benefits. But the water should not be completely absorbed into the cereal. Drain the water - it will play the role of this invisible ink. Remember how it was mentioned earlier that paper contains a lot of starch? Well, rice contains even more starch, so lubricate the leaf with an aqueous solution of iodine - and the contrast of colors will allow you to read the message without any problems. They say that this method has been known since the time of the Chinese emperors, but I could not find exact confirmation of this fact.

How should I write so that it is visible under ultraviolet light?

As a good fluorescent ink, you can use regular laundry detergent containing optical brighteners. After diluting the powder with a small amount of water, you can begin to write.

secret message.

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Three simple secrets to creating invisible letters

Let's look at the most common ways to make disappearing ink at home.

1. Iodine-dextrin filtrate. We will need dextrin (1 teaspoon), iodine (medicinal solution) 50 ml and filter paper. Mix iodine and dextrin, shake thoroughly and wait for precipitation. Then we filter and use the resulting liquid as ink. They will disappear because iodine is very volatile, and it is this that provides the color. It takes about three days to disappear.
2. Willow ink. We will need a small willow twig. It must be burned, and the resulting ash must be thoroughly crushed and diluted with water to such a state that it can be used for writing. Such inscriptions will disappear in about 5-6 days.
3. Sympathetic alkaline ink. To prepare them, you will have to go to the pharmacy and buy several chemical ingredients. Namely:
   ethanol;
4. aqueous solution of ammonia (ammonia);
5. phenolphthalein (purgen);
6. water.

Preparation: mix 100 ml of ethyl alcohol with one teaspoon of purgen until the latter is completely dissolved. Then add water (50 ml) and one cap of ammonia to the solution. The substance will turn bright red. Now you can write anything, anywhere with this ink. As soon as they dry, they will immediately disappear.

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It is important! When working with any of the listed substances, you must observe safety precautions and extreme caution!

How else can you show the inscription made with lemon?

Another way to manifest a code written in invisible ink is to use regular iodine from your home medicine cabinet. Its action differs from the thermal method in that it colors not the inscription itself, but the paper on which it is applied. The fact is that iodine is not able to react with citric acid. As a result, what you applied to the sheet with it remains white while the paper turns yellow from iodine.

In this secret way, you can write secret letters to each other and draw pictures. And this is a guarantee that only a person privy to the common secret will see your message or creativity.