Naked Science Forum

On the Lighter Side => That CAN'T be true! => Topic started by: MarkusON on 19/08/2009 15:41:53

Title: Sunglasses that can see invisible INK
Post by: MarkusON on 19/08/2009 15:41:53

Hello its me again, I didnt know in which forum to post my question so ill just post it here.

Are there any sunglasses \ special glass that can see invisible ink??

I heard something about making some polarizing material and polarizing sunglasses thats all. [?] [?]

Title: Sunglasses that can see invisible INK
Post by: MarkusON on 20/08/2009 11:15:06

true or not??

Title: Sunglasses that can see invisible INK
Post by: Nizzle on 20/08/2009 12:22:41

Are you interested in the sunglasses, or just in writing some secret stuff with invisible ink? 'cause the latter can be done much easier than special sunglasses...

Title: Sunglasses that can see invisible INK
Post by: Chemistry4me on 21/08/2009 05:32:32

Quote from: MarkusON on 20/08/2009 11:15:06

true or not??

You'll find some here: http://www.advanced-intelligence.com/invisibleinkglasses.html

Title: Sunglasses that can see invisible INK
Post by: Madidus_Scientia on 21/08/2009 12:40:48

I bet you just want to cheat at poker by writing on the back of all the cards!

Title: Sunglasses that can see invisible INK
Post by: MarkusON on 21/08/2009 14:31:23

Quote from: Chemistry4me on 21/08/2009 05:32:32

Quote from: MarkusON on 20/08/2009 11:15:06

true or not??

You'll find some here: http://www.advanced-intelligence.com/invisibleinkglasses.html

I would like to know if these sunglasses are true or fake thats all.

and im not playing poker.

Title: Sunglasses that can see invisible INK
Post by: Chemistry4me on 22/08/2009 04:22:17

Apparently they do work:

http://inventorspot.com/articles/spy_glasses_allow_you_read_invisible_messages_28631

Title: Sunglasses that can see invisible INK
Post by: MarkusON on 23/08/2009 12:31:19

I saw that site, there is no evidence that they work, thats why I ask you guys.

Maybe some video proof will do it.

Title: Sunglasses that can see invisible INK
Post by: scalyblue on 30/08/2009 09:05:45

given that ink can be polarized and the sunglasses are polarized in the same way, this could be the case, but nothing would stop somebody without the glasses from being able to see the ink at the right angle.

Now you can certainly design an image to only show meaningful data when viewed through certain glasses; I don't beileve that there is an ink that can do this, unless the glasses are actually displays for some sort of camera; that would make them something besides sunglasses though.

Title: Sunglasses that can see invisible INK
Post by: MarkusON on 01/09/2009 14:46:30

Got it !

thanks !

Title: Sunglasses that can see invisible INK
Post by: techmind on 01/09/2009 23:37:46

In principle, you could make an ink which absorbs only a very narrow band (colour range) of light - enough that it's barely noticeable. You could then have some narrowband filters in the glasses which would 'reveal' the ink.

You can do this crudely and faily easily with yellow ink (which isn't very visible normally) and a deep-blue filter.

Many brands of colour laser printers print a hidden yellow dot-code on all their printouts which encodes the printer serial number and the time and date of the print. If you use the printer for making forged documents, it can aid tracing the source.
If you view the printouts using a deep blue LED light and an eye-glass then the (normally invisible) tiny yellow dots appear as black dots.

http://w2.eff.org/Privacy/printers/docucolor/


You might also use a narrowband near-infra-red absorbing ink, and a narrowband deep red filter. With normal light sources the eye's sensitivity will be swamped by the more visible wavelengths, but with a filter (and deep-red rich lightsource such as a tungsten bulb) you could reveal hidden printing.


Narrowband inks are fairly rare and expensive I believe.
With them, you could play games with making things that look very different under fluorescent (5 narrow spectral bands) from tungsten/sunlight (broadband emitters) too.

Title: Sunglasses that can see invisible INK
Post by: scalyblue on 02/09/2009 03:11:22

Well using an ALS is cheating ^.^  and OP specified invisible, not yellow; but I'm just being pedantic.