EXPERIMENT-
10
Prepared
& presented by- Ayushi Mittal
Objective:
To decipher secret writing from surface of paper.
Requirements:
1. Secret
writing samples
2. Transmitted
light chamber
3. UV
chamber
4. Candle
5. Lemon
juice
6. Milk
7. Camera
8. Gloves
Theory:
Clandestine
writing is any means of written communication where the actual written text is
not visible or readable to the naked eye. It is about discovering hidden or
hidden writing. Different methods of secret writing can be invisible inks,
miniature fonts, which means text written in small letters, latent photographs
that are invisible to the naked eye, ciphers and codes. The most common method
used in secret writing is invisible inks, other methods are developed over time
with technologies that develop in the field of secret writing.
Invisible
inks can be sorted into three basic classes:
1.
Those exposed to heat
2.
Revealed by a chemical reaction
3.
And those that are immediately recognizable under ultraviolet light
The
nature of inks varies greatly, it can be a simple substance or a complex
substance, simple substances such as water, body secretions, fruit juices, soap
etc. and complex substances such as chemicals can be used.
In
general, invisible inks can be classified as sympathetic inks and organic fluids.
. Organic fluids contain many substances, such as lemon juice, sweat, saliva,
vinegar, milk, onion juice, urine, which can evolve with heat. These organic
fluids change the fibers of the paper and when exposed to heat at a lower
temperature, the secret writing turns brown faster than the surrounding paper.
On the other hand, a sympathetic ink that contains at least one chemical and
requires the use of a specific reagent to be developed.
Invisible
ink is a form of steganography, i.e. hiding a message. A secret writing
experiment involves dipping a brush in fruit juice or any organic liquid and
writing on a piece of blank paper. When the liquid dries, it will be invisible
to the naked eye, but if the paper is held against a heat source, it can be
hidden. Secret writings written using fruit juices, chemicals and bodily fluids
turned brown when heated. This is because these liquids are either acidic or
alkaline in nature, which weakens the paper as a result. After the water
evaporates from the paper and the liquid dries, the acid or base present in the
liquid still remains in the paper. And when the paper is held near a heat
source, the part of the paper containing the acidic or basic parts turns brown
faster than the rest of the paper, which does not contain any dry liquid
containing the acidic or basic part, thus cracking the secret message.
Method:
- 1. Two
samples were made using milk and lemon juice.
- 2. A
sample suspected of containing secret writing was observed under normal light,
transmitted light, and photographed.
- 3. The
sample was then exposed to heat using a candle.
- 4. Once
the writing was completely visible, the heat source was removed and the sample
was photographed.
Procedure:
- 1. The
sample suspected to contain secret writing was observed under normal light, and
transmitted light and photographed.
- 2. The
sample was then observed under long UV and short UV light and photographs were
taken.
- 3. The
sample was then exposed to heat using a candle.
- 4. Once
the writings were completely visible the heat source was removed and the sample
was photographed.
Observations:
Sample
1: Write what was seen.
Sample
2: Write what was seen.
EXAMPLE:
SAMPLE
1: SMILE
SAMPLE
2: HAPPY
Results:
The
secret writings were successfully deciphered.
Precautions:
1. Protecting
gear must be worn while performing experiments.
2. The
sample must be heated carefully without exposing it to very high temperature.
3. The
UV cabinet must be switched off after use. Direct contact with UV light must be
avoided.
4. The
flap of the UV chamber must be closed while using.
5. Sample
paper should not be burned while using candle.
Click here video to watch this practical in video form.
