TravisDeyle.com

There was a very interesting post on Gizmodo the other day about "How to Make Glow-In-The-Dark Printer Ink." 

Not to spoil the video or anything, but you take glow-in-the-dark powder, mix it in with printer ink, microwave it, suck it into a syringe, then inject it into an empty cartridge. Once it's printed, you can turn off the lights and see your hard work. As delicious as that glow-in-the-dark solution is when it comes out of the microwave, you probably won't want to drink it.

It would be neat to use an "Epson Continuous Flow" system full of different colored glowing inks so that you could print your own glow-pictures or glow-signs.

Now, the inks can be purchased (quite cheaply) in a variety of colors from companies like Glow, Inc. Now, these would be great for home use, such as advertisements and fun banners (or on your car, skiis, whatever).

Here are some of the colors (and their prices/descriptions) from Glow, Inc.

	Ultra Green v10 Glow in the Dark Powder Brightness Rating: Very High (~33000) Duration: Very Long (12+ hours) Glow Color: Green-Yellow Daytime Color: Almost Clear with White-Green Tint Not compatible with water-based mediums Brightest Glow Powder Sold Anywhere $8.74 per 1 oz.
	Pure Blue Glow in the Dark Powder Brightness Rating: Medium (3209) Duration: Medium (3 hours) Glow Color: Sky Blue Daytime Color: Almost Clear with White-Blue Tint Works well with water-based mediums Impressive Pure Sky Blue Color   $5.59 per 1 oz.
	Zinc Red Glow in the Dark Powder Brightness Rating: Medium (3853) Duration: Short (10 minutes) Glow Color: Deep Red Daytime Color: Red Works well with water-based mediums Has a strong odor unless sealed by a medium Pure Blood Red Color   $14.39 per 1 oz.
	Zinc Orange Glow in the Dark Powder Brightness Rating: Medium (3821) Duration: Short (10 minutes) Glow Color: Deep Orange Daytime Color: Orange Works well with water-based mediums Has a strong odor unless sealed by a medium Deep Orange Glow   $14.39 per 1 oz.
	Purple Glow in the Dark Powder Brightness Rating: Low (913) Duration: Short (30 minutes) Glow Color: Deep Purple-Blue Daytime Color: Almost Clear with White Tint Not compatible with water-based mediums Awesome Deep Purple Effect   $5.59 per 1 oz.
	White Glow in the Dark Powder Brightness Rating: Medium (2471) Duration: Medium (2 hours) Glow Color: White Daytime Color: White Pure White Color   $19.79 per 1 oz.

OK, you get it. There are all sorts of colors to make really cool signs. So how does this create a covert channel (aka, a hidden message)? Well, look at the last two powders. They both have "daytime colors" of white or clear-white. I'm guessing that if mixed with in a clear ink (or maybe just water, even), any text on a printed sheet of paper would be almost indiscernible (under normal lighting) once the ink dried!

All that a nefarious individual needs to do is subvert the ink cartridge on a "secure" printer (one that prints important/controlled/sensitive documents), print away until someone replaces the cartridge (thinking it is empty), and then exit the facility with a bunch of seemingly "empty" sheets of paper. The scheme is even more likely to avoid detection if the printer is only accessible by the nefarious individual. Of course, it all hinges on the ability of the papers to avoid close inspection (namely, in the dark). However, at a quick glance, I'm fairly certain that the pages would go undetected.

Essentially, this is a fun twist to the typical disappearing, reappearing ink. Cool idea, eh?

Anyway, I've never built any custom (let alone "glow-in-the-dark") ink, so I haven't got a clue as to whether or not this would actually be successful. However, it is a compelling idea worthy of exploration.

Any thoughts?

NOTE:  This post originally appeared on Hizook.com, which has been transformed into a robotics-centric website.  To preserve all of my original posts, I've transferred the content to my new homepage TravisDeyle.com.  I also encourage you to scope out the new Hizook!