Thread: Chemical question?

ok I have this one question........ok this is what I want to do.....put a image on a surface but it is unseeable....then spray a liquid like water over the surface later and the image appears.


how to do this????

We call this 'writing with invisible ink.' There a several simple ways. One well-known method is to write on paper with lemon juice. The writing is invisible at first. When the paper is heated, the writing darkens.

Maybe the other people can suggest other ways.

All I can suggest is the chemicals used in old fashion cameras

HAHA, ethidium bromide? you can get the stuff to show by shining UV on it afterwards. just that it is carcinogenic though :wink:

Originally Posted by lynnity

just that it is carcinogenic though :wink:

That just adds to the excitement

I'm pretty sure that I've heard that milk can be used for that, but I could be totally making that up...

cool thinks for the ideas....I'm wanting to hopefully be able to do it so the image shows up in purple...or shows up enough to amaze people.


I want to put the invisable liquid in a stamp pad...and use a stamper to put the image on the wall......thus making it invisable till later...then I want to be able to spray water {or some other liquid} over the area and the image appears and amazes people.


I'm hoping this could be done on like concrete, metal, plexiglass, glass, and stuff like that.

I used bug and tar and got the area to darken in the shape of the image when sprayed with water but no color.......car wax basically did the same thing {probally because maybe bug and tar may have car wax added?}.

Originally Posted by SteveF

We call this 'writing with invisible ink.'

LOL
This reminded me of a thing that happened in my class few years ago.
It was a lesson and the teacher checked our homeworks. One pupil hadn't done his homeworks and teacher asked what was the excuse.
The pupil answered: "I had an ordinary pen and a pen that has invisible ink in it on a table, and I accidently used the pen with invisible ink."