Introduction: Super Simple Heat Activated Invisible Ink (not Lemon Juice)

5min $5 invisible ink utilizing the already-there heat sensitive chemical on thermal paper. I think this works much better than lemon juice because lemon requires you to half burn the paper to show up.this requires much less heat.

Step 1: Get the Stuff You Need (not Much)

you need,

1.thermal paper

2.water and a cup

3.tooth picks/q-tips (to write with)

4.candle or other heat source

NOTE: If you dont have blank thermal paper just use receips from stores and gas stations (use only the paper that is shiny on the one side with dark shiny black writing). Be sure to use the part that is blank and not the printed on part.

Step 2: Add Paper

fully soak in water

Step 3: Remove the Heat Sensitive Chem

remove as much water as possible. If you have a tea bag strainer/smusher thiny it would work well.

Step 4: Finish

keep wetting and wringing out the paper untill your ink looks like whats in the pic below. the more concentrated your ink the better it will work.

Comments

author
nomooremr.niceguy made it! (author)2012-03-08

Does this ink remain visible? or does it disappear when it cools down again? Thanks for your input.

author
invitediva made it! (author)2010-08-30

i became a pro member thinking there was step after step 4 --- i have done everything and have been able to get the liquid to look milky but when i use a q tip to apply it to paper and heat the paper, nothing happens. any thoughts.

author
nutsandbolts_64 made it! (author)2010-08-12

waaaaaait........ you mean I could use old receipt paper for that? as in the modern receipt paper? the smooth-feeling paper? if so, I'm buying a roll! lol

author
stone3408 made it! (author)2007-01-11

While we are on the topic of thermal paper. There is a chemical out there that will react with thermal paper and turn it black. It is sort of a yellow color. Any thought on what that maybe.

author
X_D_3_M_1 made it! (author)X_D_3_M_12007-11-10

iodine?

author
stone3408 made it! (author)stone34082007-11-18

That works but, I'm looking to use it in fingerprinting application and iodine to too hazardous.

author
scratchr made it! (author)scratchr2010-06-09

You should worry more about what is in the paper. (hint:Bisphenol A)

author
X_D_3_M_1 made it! (author)X_D_3_M_12007-11-18

o. u could do corn starch and iodine, starch turns purple/black, if u didnt mind danger

author
Fenwick made it! (author)Fenwick2007-05-20

I know Alcohol turns thermal paper black sometimes. It's not very consistent though.

author
instructa-fan made it! (author)2007-09-30

correct me if i'm wrong, but what this is, is soaking thermal paper in water which gets some funky chems in the water and this will be your thermal activated ink??? or do you write on a reciept???? i'm confused...0\ _ /0...grr...

author
lasermaster3531 made it! (author)lasermaster35312010-03-29

the chems in the water is the ink.

author
thejrb made it! (author)2007-03-02

You spell it Receipts.

author
technodude92 made it! (author)technodude922008-01-04

I before E except after C...

author
killerjackalope made it! (author)2008-01-02

Great source of thermal paper is fax machine paper for old school ones, you can still buy it at most places like staples and it's pretty cheap for a large ream...

author
usuck made it! (author)2007-02-28

for the ink

author
usuck made it! (author)2007-02-28

can u use regular paper?

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pyro22 made it! (author)2007-02-26

yea regular paper

author
pyro22 made it! (author)2007-02-25

im not sure what the problem could be but i would guess that your thermal paper is different that mine or the theremal chemical is not concentrated enough. How much paper to water did you use?

author
playingwithfire22 made it! (author)playingwithfire222007-02-25

it looks exactly like yours throughout the steps. Mine may be to watery so ill try less water to more paper. Also you use this on regular paper and not the thermal paper right?

author
playingwithfire22 made it! (author)2007-02-24

Sorry to bother, but I am having trouble with this. I follow all of the steps. I put thermal paper in the water and wring it till it turns whitish. I then apply some to a piece of paper and wait for it to dry. I then hold a lighter to it and nothing happens except maybe a brown mark from me burning the paper. Any thoughts on what i could be doing wrong?

author
foney_email made it! (author)2007-01-17

I hear Urine works as invisible ink. I have never tried it though.

author
pyro22 made it! (author)2007-01-12

you can usually find thermal paper in office supply stores as it is used in fax machines, printers etc. or can use old cut up recepts, just make sure its thermal paper and not ink on regular paper

author
Vertigo666 made it! (author)2007-01-12

just wonering, where would you buy thermal paper?

author
jgodsey made it! (author)2007-01-09

I'm lazy I prefer Noodler's Blue Ghost invisible Ink but this is a handy backup!

author
IlluminatedAntichrist made it! (author)2007-01-09

Cool, i'll try it.

author
dcshoeco33 made it! (author)2007-01-09

thats really cool

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