/PSA addendum

For those who didn't pick up on this, the ink that you use in your printer was formulated by the manufacturer to work properly when heated and passed through the printhead. The invisible ink contained in a pen is not. It may be more or less viscous than printer ink, and can damage the printhead, hence the cautionary text above.

Having said that, go print up your invisible, ROT-13'd secret messages for your friends to crack with their blacklights and Cracker Jack decoder rings. ;)

It_Figures

Neat trick, but if you're going to try it, just be sure to do this with a printer that uses tri-color cartridges (Cyan, Magenta & Yellow in the same cartridge).

Why?

In every inkjet printer, ink passes out of the tank, through the printhead (the part with the hundreds or thousands of tiny nozzles that drop the ink onto the page), and finally onto the page.

Tri-color cartridges have a built-in printhead. Every time you buy a new cartridge, you buy a new printhead.

Therefore, if you get unlucky while trying this little experiment, the worst-case scenario is that you're out ~$30 +/- $10 for a new cartridge.

Contrast this with printers that use individual ink tanks for each color (Cyan, Magenta, Yellow, Black, and possibly others like Light Cyan/Light Magenta/etc. for photo printers).

These individual ink cartridges do not have disposable print heads. They all rest in a printhead that may or may not be user-replaceable. Usually, when the printhead is user-replaceable, it costs more than a cartridge costs, and you're not likely to find one at, say, Staples or Best Buy.

So kids, exercise caution before you hose up mom's printer. ;)

/end PSA

It_Figures

Sweet! If I only knew about this in middle school...

Paul

Um, and don't use this to make fake IDs, kids.

ffejie

I'm off to start my new career as an international spy, with a license to annoy. To see where my first mission is, use your magic decoder, on the following space of invisible text:

Meet you there.

Duane

Noodler's makes the UV invisible ink by the bottle:

[www.pendemonium.com]

(scroll)

Fountain pen people tend to be a bit more picky than others when it comes to ink--you might have better luck than other choices.

I've heard of using fountain pen ink to refill cartridges. Not sure how cost effective it is, but I know there are a bunch of interesting choices.

MrGuilt

Hehe, this should be a good April Fools joke for next year...

LegosJedi

Can't you just fill up the black print cartridge? That way you don't need to change black text to yellow.

nintendude

*Sigh*...i know the background music is royalty-free and all, but ergg why did he have to use the one we made for our video???? Haha awesome trick!

jordanswogger

Yes, but then printing in black ink would be rather difficult, don't you think?

Popsonian

Hm, use black instead? I think they use yellow just in case there is some residual ink, and I think black tends to get noticed sooner :)

Wouter

> It's a fun way to cover up sensitive documents

No, it's not. Even after the ink 'disappears', the paper can still be read quite easily, And in any case, I doubt that the invisible ink designed for pen use is similar enough to ink designed for printers that it won't gum up the works in short time.

dotancohen

Make sure that the color is exactly the color inside it. Computer shades of color may add a bit of blue or red to tint the color correctly.

Brad

@ffejie: Hahaha! That was clever. :)

Silver_Back

I don't have the time or patience to do this, but I'm pretty sure the result won't be worth it. That's just my opinion. I mean why find an invisible ink pen, take the time to fill up an old one, take out your current cartridge, and put it in there just to print a "document" or whatever?

math_boy

I stand corrected... HP offers UV/IR ink cartridges...

Why are there not available here i dunno but they exist!!!

whiskey

So... how about this HP? Lexmark? Who is going to make the first commercial invisible ink tanks?

whiskey

i just tried this.Very cool result.I had print 100 sheet and no probleme with the cartridge.I use that for making my precious document top secret.Thanks life hacker

sharafisher

You know, back in the day of ribbon-based-ink, AKA dot-matrix printers, you could "revive" your ink ribbon by spraying WD-40. That was by far the cheapest (and invisible!) ink solution. I could perform this trick 3-4 times before the ink ribbon actually ran out of black ink. The only downside is that if you sprayed too much, your ink might bleed on paper, but it was definitely cheaper than buying ink! It's just too bad the majority of printers these days are inkjet or laser so there isn't a trick that can match it yet!

JohnD65

Cool, but mostly useless. And won't work on my laster printer...

Dereks