How to make invisible ink, how to make invisible ink?

Lemon ink uses a strainer to filter freshly squeezed lemon juice and then dips the tip of a pen or a sharpened stick into writing. In order to re-create the characters written in this ink, the area of the text must be carefully heated on the radiator. The text appears brown when it is revealed.

Onion ink churns an onion into a paste. Place these pastes in a tea strainer and hydraulically squeeze out the juice with a spoon. Text written in onion ink will appear black when heated.

Be careful when making this ink, because it will shed tears, and vinegar ink requires white vinegar. White vinegar itself has no color, and it can be heated to reveal the characters written in vinegar ink. What is Water WritingThis secret writing does not require special ink, you only need to prepare two blank sheets of paper, a window pane or a mirror, water, and a soft pen.

Dip a piece of paper in water, carefully pick it up again, and lay it flat on a windowpane or mirror. Then cover it with dry white paper and write the text on it with a soft pen. Then peel off this dry white paper, tear it into many pieces, and throw it into different waste cartons.

After the wet blank paper dried, the secret information was written. The paper looked empty and unobtrusive. In order to disguise it better, you can also write anything on it in a place where there is no water text.

The recipient only needs to put the letter in the water to read the secret information on it.

Method 1 (with pH test paper) Put a piece of pH test paper into less than 50ml of water and stir vigorously until the pH test paper is basically crushed. Use a brush to dip the thick lime milk and write it on paper. When it is revealed, it is manifested by splashing water soaked in pH test paper on the paper.

2 (without pH test strip) use a candle to write on a piece of white paper, and be realistic. When it is revealed, the paper is immersed in diluted iodine (iodophor), and it comes out.

I used to read in books that I used to write with ink from a cuttlefish ink fountain, and it would disappear after a while. If you want to save it, draw a layer of mud on it

Lemon juice, wash it with a pen and then write, dry it will be invisible, and then roast it with fire, the place where the lemon juice has been written will soon turn yellow and the handwriting will naturally come out, pay attention to safety when baking, don't ignite the paper. The brush is dipped in starch to write, and when you read, apply iodine water to the paper. This is the principle of using iodine and starch for color development.

It's very simple, lemon juice is sucked with a pen and then written, and when it dries, it is invisible, and then roasted with fire, the place where lemon juice has been written will quickly turn yellow, and the handwriting will naturally come out.