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How To Make Invisible Ink: A Detailed Guide

Updated on November 29, 2013
susi10 profile image

Susan is a science geek, and if that wasn't enough, she gets all nerdy over technology too. She is also a writer too.

The Five Methods

Today, we will focus on five methods. Here they are:

  • Lemon Juice
  • Baking Soda
  • White Crayon
  • Invisible Ink Pens
  • White Pencil and Newspaper

Invisible Ink: An Introduction

Making invisible ink is a fun way to hide your passwords or anything that you don't want to be read and can be done quickly and easily using household materials.

This is a fun idea for children, they can make invisible ink to pass secret notes to their friends or play secret agent for the day! It is a great science experiment for any parent to do with their child.

If you have been wondering how to make invisible ink but don't know how to, then this is the hub for you! This guide will explain exactly what you will need and what you have to do to make your ink, and then reveal it once more. There are five methods, which will each be explained one by one, just in case you don't have some of the materials in the other methods.

Making invisible ink with lemons is really easy!
Making invisible ink with lemons is really easy! | Source

Did you know?

By making invisible ink with lemon juice, you are actually doing a scientific experiment in a branch of science called 'Acids, Bases and pH'.

How To Make Invisible Ink With Lemon Juice

The first method is making invisible ink with lemon juice. This method is the most popular method and requires the least materials. Here is how you do it.

  • Firstly get a lemon, cut it in half and squeeze all the juice from it. Then take out any seeds from the juice.
  • Get a paintbrush and dip it in the juice. Then, making sure your paintbrush is saturated with lemon juice, start writing your words on the paper. As youw rite your message on the paper, you will notice that the message is still visible. Don't worry, as the paper dries the message will disappear completely.
  • Leave the paper to dry.

How It Works: The lemon juice is acidic so when it is heated up, it turns a brown colour quicker than the paper does. This experiment can also be done with other acidic substances such as water with vitamin C effervescent dissolved in it. Just make sure your acidic substance is invisible, so don't go trying it with tomato juice which is also an acidic substance.

How To Reveal Your Message: Once your paper has dried up, it is time to reveal your message! Simply place the paper near something hot and allow the paper to heat up. You can do this by blowing a hot hair dryer onto the page, or placing the page in the oven for three to four minutes. Or, you can iron the page, just be careful when ironing with children around. Or, you can place the page on the radiator for half an hour to heat up. As it does so, you will begin to see your message appear in brown writing on the page.

Grape juice is used to reveal your invisible ink which is a baking soda solution.
Grape juice is used to reveal your invisible ink which is a baking soda solution. | Source

How To Make Invisible Ink Using Baking Soda and Grape Juice

The second method you can use is making the ink with baking soda. You will later use grape juice to reveal your secret words or message. This method works similarly to the lemon juice method but instead of heating the paper up, you simply spread grape juice on the paper.

You will need a small paintbrush, a page, grape juice and milk.

  • Add four table spoons of baking soda to half a cup of water and stir thoroughly.
  • Then, dip your paintbrush in the milk and begin writing your message on the paper. The message will be quite easy to read at the start, as it is still wet but as it dries it will eventually disappear. Leave the paper to dry.

How To Reveal The Message: To reveal your message using another clean paintbrush, dip the paint brush into grape juice and spread it over the paper. Your message should appear in a lilac colour on the paper.


You will need watercolours for this method.
You will need watercolours for this method. | Source

How To Make Invisible Ink Using White Crayons

You can make invisible ink using a white crayon. Whilst it may not seem like 'ink', it still will look invisible when you write on the page. The oil-based wax from the crayon is what will make the message to reveal itself later on. This method is very effective, as the message will appear very clearly on the page. It is perhaps more effective than the baking soda method.To reveal the message, a watercolour based paint will be used.

You Will Need: A White Wax Crayon, a watercolour based paint (preferably a darker colour, perhaps red, pink, purple or blue), paper, paintbrush.

To make your make an invisible message from your white crayon, firstly write your message on the page. You should find it almost impossible to see the message. Then, pick a colour from your watercolour paints and gently paint over the message. As the crayon is made of wax, it contains oil and oil repels the watercolour paint so the watercolour paint won't paint over the message. You should clearly see your message in white written on the page.

You can do this on newspaper or normal paper.
You can do this on newspaper or normal paper. | Source

Write a Secret Message on Newspaper with a White Pencil

This method is particularly handy if you want to write a secret message to someone but don't want it to be intercepted. A newspaper doesn't look suspicious, right? If someone intercepted it, all they'd see is a bunch of black text and nothing else. Here's how to do it.

  • Get a sharp white pencil and write a message on a blank part on the newspaper. Make sure to very strongly indent the pencil into the page, as the indent will be needed to reveal the message.
  • Then, to reveal the message, all you have to do is to get a black/blue pencil and lightly colour over the message. The indent will make sure the message won't be coloured on so you can see the message.

Or, if you're too lazy...

Maybe you don't feel like making your own invisible ink right now, so why not try these invisible ink pens? They are both of very high quality, are practical and work beautifully. You don't have to be a kid to buy one, they can be super useful if you want to conceal secret passwords for your various Internet accounts, PIN numbers and lots more!

They use a special UV revealing ink, which when shone with the UV torch on the other end of the pen, the writing glows and lights up, allowing you to read the message.

A Complete Demonstration and Tutorial

Would you like to make invisible ink?

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    • susi10 profile image

      Susan W 3 years ago from The British Isles, Europe

      Thank you Flourish! It is a good idea for those who really want to protect their passwords.

    • FlourishAnyway profile image

      FlourishAnyway 3 years ago from USA

      I like the idea of writing passwords in invisible ink. Super sneaky!

    • profile image

      biochemi 4 years ago

      Thanks susi10!!!

    • susi10 profile image

      Susan W 4 years ago from The British Isles, Europe

      Hi biochemi,

      It's nice to meet a science (biochemistry) Hubber here, thanks for dropping by and for commenting. I am glad that you tried out the experiment with the lemon juice and for sharing your results, doing these experiments can be quite fun!

      By the way, you have some great science hubs, I am looking forward to reading more of them.

    • profile image

      biochemi 4 years ago

      Nice hub. I had tried using lemon juice and the result was same, as described here.

    • susi10 profile image

      Susan W 4 years ago from The British Isles, Europe

      Thanks for reading and taking the time to comment, hazelwood. I hope that you have learned a lot from this hub, and in how to make invisible ink, you'll never know when you might need it!

    • hazelwood4 profile image

      hazelwood4 4 years ago from Owensboro, Kentucky

      This is a really good Hub. What an interesting idea. Keep those Hubs coming.

    • susi10 profile image

      Susan W 4 years ago from The British Isles, Europe

      Thanks for reading this, Wild_Life! I hope you find this hub useful.

    • Wild_Life profile image

      Wild_Life 4 years ago from portugal

      Very good...