Invisible ink in Wuxia fiction

[bloodstar]

In HSDS, Xiao Zhao used her own blood to reveal the hidden text on the QKDNY manual. This invisible ink technique is a cliche in wuxia fiction and movies, but is it based on any scientific principles or is it pure fiction rubbish? I know lemon juice can be used as photosensitive invisible ink... are there other known methods based on chemical reaction perhaps?

Also, besides using blood, are there any other methods used in wuxia fiction to reveal hidden text?

[kamii]

LOL this.....

there also the burning of the paper and then putting it into watER!!! XD

An empty book but then u burn and then put the book in water and the characters will appear! ROFL

[miette]

This invisible ink technique is a cliche in wuxia fiction and movies, but is it based on any scientific principles or is it pure fiction rubbish?

I believe it's possible in reality. My biology lecturer mentioned this to our class once (though my friends and I were busy discussing about Bo Bice and didn't pay much attention). Actually, Agatha Christie and Mary Higgins Clark also used this in their books.

[Suet Seung]

LOL this.....

there also the burning of the paper and then putting it into watER!!! XD

An empty book but then u burn and then put the book in water and the characters will appear! ROFL

NO. OMG! You don't burn the paper!

First you try hovering the paper OVER the flames of a candle thus the heat from the flames would make the words appear. But careful not to put it too close to the flame or else it would burn(no duh.

If that doesn't work then you put it in water or use a brush to paint water on the paper to see if the words appear (like SOD1996).

[kamii]

NO. OMG! You don't burn the paper!

First you try hovering the paper OVER the flames of a candle thus the heat from the flames would make the words appear. But careful not to put it too close to the flame or else it would burn(no duh.

If that doesn't work then you put it in water or use a brush to paint water on the paper to see if the words appear (like SOD1996).

LOL i was thinking about that! If u actually burnt the paper then it would just turn into black ashes! I see now haha.

Now........where'd i keep that 'no word' kung fu book.....

[convoy]

A Wikipedia article on invisible inks.
http://en.wikipedia.org/wiki/Invisible_ink

<snip>
Revealed by heat

Some of these are organic substances that oxidize when heated, which usually turns them brown.

* Milk
<snip>
* Urine
<snip>

A very convenient invisible ink, but eeww. Imagine an entire "no words" kungfu manual written in it.

[kamii]

LOL....that's a pretty funny find....

hmm i can go and my my 'no word' kung fu manuals now.......hehehehe