What magical uses did invisible ink have in ancient history?

Why was there a need to invent invisible ink in ancient history?

In the era of the Spring and Autumn Period and the Warring States Period, when the princes were fighting each other, the confidentiality and transmission of intelligence were related to the success or failure of the war. In order to ensure the security of important information, people began to try various methods to hide text, and invisible ink came into being.Most of these early invisible ink were derived from nature, such as lemon juice, milk, and alum. They were perfectly invisible under normal light and would only reveal their true appearance after heating or using specific chemical reagents. Therefore, spies often used invisible inks to convey intelligence.

Where did the idea ofmodern invisible ink originate?

The prototype of modern invisible ink can be traced back to alchemy in the Middle Ages. Chemists at that time discovered in experiments that some chemical substances could show color under specific conditions. For example, they could crush "goiter" and dissolve them in water for writing letters. After wiping them with a sponge soaked in sulfate, the text would magically appear.

What is the significance of invisible ink in the military?

By the time of World War I, invisible ink had become an important secret weapon for spies. Both the U.S. Naval Intelligence Agency and Germany used complex invisible ink formulas. For example, the Germans mixed acetylsalicylic acid with pure water, or potassium iodide, tartaric acid, soda water, potassium cyanide and ordinary ink. These formulas required specific chemical reagents or heat to reveal the text.

Modern invisible inks have a wider range of applications

With the advancement of science and technology, the production and application technology of invisible ink is also constantly innovating. Modern invisible ink can not only be colored by heating or ultraviolet irradiation, but also appear under light of a specific band, which makes it have a wide range of application prospects in the fields of anti-counterfeiting and security. High-end goods and medical packaging, such as alcohol, cosmetics, luxury goods and prescription drugs, all use invisible ink technology to prevent the influx of counterfeit and inferior products.

Why not try an invisible ink DIY experiment to experience it?

In fact, it is not difficult to make an invisible ink experiment. A simple home experiment can achieve it:
Step 1: Squeeze lemon juice and use it as ink
Step 2: Write a message on white paper with a brush or cotton swab
Step 3: When the paper is completely dry, the message will "disappear".
Step 4: Heat the paper with an alcohol lamp, and the originally invisible text will gradually appear.

Prepare small experimental props such as lemon, alcohol lamp, brush, etc.

Write on paper with a brush dipped in lemon juice.

After the water dries, the text disappears completely.

After using an alcohol lamp to steam and bake, the text magically appears again.

OBOOC fountain pen invisible ink brings you a new romantic writing experience.

This fountain pen invisible ink is smooth and delicate without clogging the pen. It can easily handle even fine strokes and is suitable for daily notes, graffiti and even anti-counterfeiting markings.
Its characteristics are that it is easy to dry and the strokes are clear without blurring the paper. It forms a stable film immediately after writing to avoid blurring the handwriting. The environmentally friendly formula is safe and non-toxic, making writing more secure.
The invisible effect is excellent. The handwriting is invisible under normal light, and it is like stars under ultraviolet light, full of romance, bringing endless surprises to curiosity lovers.
Whether it is creative expression or private record, this ink is an ideal choice, allowing the fun of writing and exploration to coexist.

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