Invisible Ink and Secret
Messages
Messages
Ink
Soak the nails (or steel wool) in the cleaning solution to degrease.
Transfer to a non-metallic container and cover with white vinegar.
Soak for 48 hours. Boil tea - 3 or 4 tablespoons per cup of water -
several minutes. Add equal parts of the nail juice and tea. Mix in a
little mucilage or glue until it is thick enough to write with. Once on
paper, the ink will turn black with age. This is an old standard, and
has appeared in many books of science.
You can also make ink from old pecan or walnut shells. Crush a
dozen or so shells in a cloth. Boil in 1 cup (250 ml) of water for half an
hour to 45 minutes, or until the water is dark brown. Allow to cool.
Strain into a glass jar. Add 1/2 teaspoon (2.5 ml) of vinegar and 1/2
teaspoon of salt.
Invisible ink
Heat sensitive invisible inks are usually fairly simple organic liquids
that will appear invisible once they have dried on a sheet of paper, but
will darken when held over a heat source. Lemon juice or onion juice
work best, with milk or vinegar lagging close behind. They can be
applied with a pen or toothpick. Allow to air dry (don't use heat to dry
it). The dried paper is held some distance over a candle, or pressed
with a hot iron. There is, of course, the danger of the paper catching
on fire with the candle, or scorching under the iron, so take the
necessary precautions. It will be a little smoky, but the message
should appear fairly quickly. Prisoners of war used this method to
sneak out messages, using their own sweat and saliva as ink.
Another invisible ink
An alternative is to use a cornstarch and water mixture. Mix about 1
tsp (5 ml) cornstarch to 1/4 cup (60 ml) of water. Cook it a bit (you can
nuke it in the microwave for a minute, stirring once). Let it cool, and
write your message. Once dry, sponge it with a solution of iodine
(toxic!) and water (10 or so drops in 1/4 cup (60 ml) of water). Your
writing will appear in a dark blue, and the paper will be a lighter blue.
If you substitute lemon juice for the cornstarch solution, you will end
up with white text on a light blue background. If you are artistically
minded, you should be able to get some interesting effects using this
information.
Still more invisible ink
This one is a little tricky to do, and does not always turn out
completely invisible. The reacting chemical in the ink is
phenolphthalein, which is a component of some laxatives.
Phenolphthalein alone makes an invisible ink, but often the other
components of the laxative tablet will give the ink a color. It will still
produce a nice reaction. You need:
If the tablets you are using have a colored coating, it will need to be
scraped off. Use 5 or 6 tablets. Crush the tablets with a spoon in a
jar. Add a couple of inches of water to the jar and mix. Use this "ink" to
write your secret message. Allow to dry. To make it visible, mix four
teaspoons of washing soda with four tablespoons of hot water. Lay
the paper over a plate where a bit of water has been poured. You
want the paper to soak up the water and saturate. Carefully dribble
the washing soda solution onto the paper, allowing the drops to
spread over the entire surface. Don't touch the paper where the
message is while it is wet, as this will smear it. The writing should
appear pink.
Special Thanks
Thanks to Bizarrelabs.com for providing the experiment instructions.
- Materials
- Glass jar with lid
- Nails (alternate: steel wool)
- Vinegar
- Tea
- White Glue or mucilage
- Kerosene or safer cleaning solution for degreasing
Soak the nails (or steel wool) in the cleaning solution to degrease.
Transfer to a non-metallic container and cover with white vinegar.
Soak for 48 hours. Boil tea - 3 or 4 tablespoons per cup of water -
several minutes. Add equal parts of the nail juice and tea. Mix in a
little mucilage or glue until it is thick enough to write with. Once on
paper, the ink will turn black with age. This is an old standard, and
has appeared in many books of science.
You can also make ink from old pecan or walnut shells. Crush a
dozen or so shells in a cloth. Boil in 1 cup (250 ml) of water for half an
hour to 45 minutes, or until the water is dark brown. Allow to cool.
Strain into a glass jar. Add 1/2 teaspoon (2.5 ml) of vinegar and 1/2
teaspoon of salt.
Invisible ink
Heat sensitive invisible inks are usually fairly simple organic liquids
that will appear invisible once they have dried on a sheet of paper, but
will darken when held over a heat source. Lemon juice or onion juice
work best, with milk or vinegar lagging close behind. They can be
applied with a pen or toothpick. Allow to air dry (don't use heat to dry
it). The dried paper is held some distance over a candle, or pressed
with a hot iron. There is, of course, the danger of the paper catching
on fire with the candle, or scorching under the iron, so take the
necessary precautions. It will be a little smoky, but the message
should appear fairly quickly. Prisoners of war used this method to
sneak out messages, using their own sweat and saliva as ink.
Another invisible ink
An alternative is to use a cornstarch and water mixture. Mix about 1
tsp (5 ml) cornstarch to 1/4 cup (60 ml) of water. Cook it a bit (you can
nuke it in the microwave for a minute, stirring once). Let it cool, and
write your message. Once dry, sponge it with a solution of iodine
(toxic!) and water (10 or so drops in 1/4 cup (60 ml) of water). Your
writing will appear in a dark blue, and the paper will be a lighter blue.
If you substitute lemon juice for the cornstarch solution, you will end
up with white text on a light blue background. If you are artistically
minded, you should be able to get some interesting effects using this
information.
Still more invisible ink
This one is a little tricky to do, and does not always turn out
completely invisible. The reacting chemical in the ink is
phenolphthalein, which is a component of some laxatives.
Phenolphthalein alone makes an invisible ink, but often the other
components of the laxative tablet will give the ink a color. It will still
produce a nice reaction. You need:
- Laxative pills. They must contain phenolphthalein.
- Washing soda (or another safe alkali)
- Paper
- Water
- Jar for mixing
- Plate
If the tablets you are using have a colored coating, it will need to be
scraped off. Use 5 or 6 tablets. Crush the tablets with a spoon in a
jar. Add a couple of inches of water to the jar and mix. Use this "ink" to
write your secret message. Allow to dry. To make it visible, mix four
teaspoons of washing soda with four tablespoons of hot water. Lay
the paper over a plate where a bit of water has been poured. You
want the paper to soak up the water and saturate. Carefully dribble
the washing soda solution onto the paper, allowing the drops to
spread over the entire surface. Don't touch the paper where the
message is while it is wet, as this will smear it. The writing should
appear pink.
Special Thanks
Thanks to Bizarrelabs.com for providing the experiment instructions.
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