7 Amazing Types Of Invisible Ink

Some types of invisible ink are right there in your kitchen cupboard!

Hundreds of liquids, from fruit juices to specially formulated chemicals, can be used as invisible ink. Here we explore six of the most interesting and accessible types. We hope you’ll be inspired to make your own invisible ink at home. With a bit of practice, you too can become a master of steganography (which is the art of writing hidden messages, in case you didn’t know that already!)

How much money does a professional steganographer make? Link -via Geek Like Me

Okay, there's the million-dollar idea: 1. invisible ink inkjet printer cartridges. (Home tinkerers can flush and fill their own.) And further ideas: 2. several-color invisible ink cartridges, so a page can be printed in one pass, that can show totally different messages depending on the make-it-visible reagent you use later. 3. art-show animation using this technology. And 4. recycling, using the same paper several times by this process, an invisible palimpsest. It probably wouldn't smell very good, but offices often smell bad anyway, with all the personal care chemicals in the air and carpets and etc.

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On the web, you can leave "invisible" messages by setting the text color the same as the background color. The message can only be seen when highlighted (selected).

Every post on my blog has invisible writing. Since Google's spiders don't realize the text is "invisible", it's a simple way to include search terms without confusing readers.