# Security thread in dollar bills How? **URL:** \ **Category:** Factual Questions\ **Created:** [June 21, 2002, 4:23pm UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286 "2002-06-21T16:23:13Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![World\_Eater](https://avatars.discourse-cdn.com/v4/letter/w/f04885/32.png) [@World\_Eater](https://boards.straightdope.com/u/World_Eater)\ **Post date:** [June 21, 2002, 4:23pm UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286/1 "2002-06-21T16:23:13Z")
I’ve been reading about some new US bills coming out, and how they have all these enhanced security features. I’m not trying to counterfeit anything, just wondering how the hell they weave that security thread into $20 bills? I would image it must be an expensive process. Any thoughts Dopers? ---
**Author:** ![Max\_Torque](https://avatars.discourse-cdn.com/v4/letter/m/e9bcb4/32.png) [@Max\_Torque](https://boards.straightdope.com/u/Max_Torque)\ **Post date:** [June 21, 2002, 5:23pm UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286/2 "2002-06-21T17:23:50Z")
Not sure, but I did find this really cool information on one of the [Bureau of Engraving & Printing’s anti-counterfeiting pages](http://www.bep.treas.gov/section.cfm/7/35) (bolding mine): > [@](#): > > A security thread is a thin thread or ribbon running through a bank note substrate. All 1990 series and later notes, except the $1, include this feature. The note’s denomination is printed on the thread. In addition, the threads of the new $5, $10, $20 and $50 notes have graphics in addition to the printed denomination. The denomination number appears in the star field of the flag printed on the thread. **The thread in the new notes glows when held under a long-wave ultraviolet light. In the new $5 it glows blue, in the new $10 it glows orange, in the new $20 note it glows green, in the new $50 note it glows yellow, and in the new $100 note it glows red.** Since it is visible in transmitted light, but not in reflected light, the thread is difficult to copy with a color copier which uses reflected light to generate an image. Using a unique thread position for each denomination guards against certain counterfeit techniques, such as bleaching ink off a lower denomination and using the paper to “reprint” the bill as a higher value note. ---
**Author:** ![Belrix](https://avatars.discourse-cdn.com/v4/letter/b/ed655f/32.png) [@Belrix](https://boards.straightdope.com/u/Belrix)\ **Post date:** [June 21, 2002, 5:51pm UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286/3 "2002-06-21T17:51:06Z")
I saw a big special on money printing on TLC or A&E or similar. Anyway, they followed the whole process from start to finish except that strip. That part is secret. Ssshhhh!!! ---
**Author:** ![World\_Eater](https://avatars.discourse-cdn.com/v4/letter/w/f04885/32.png) [@World\_Eater](https://boards.straightdope.com/u/World_Eater)\ **Post date:** [June 21, 2002, 6:46pm UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286/4 "2002-06-21T18:46:48Z")
Nice link, thanks. ---
**Author:** ![femtosecond](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@femtosecond](https://boards.straightdope.com/u/femtosecond)\ **Post date:** [June 22, 2002, 11:30am UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286/5 "2002-06-22T11:30:09Z")
The threads are embedded into the wet pulp when the paper is made. For windowed security threads the paper is scraped off again at the spots where you want the thread to show. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [June 22, 2002, 1:25pm UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286/6 "2002-06-22T13:25:01Z")
That security thread (or lack thereof) once saved me $10. I went to a mini-golf place and it was $5 I handed the person a $20 and she gave me $5 back. I knew something was wrong but I was young and she claimed I only handed her a $10. So I let it go. When I got back in my friend’s mom’s car I told her about it and she went back to the booth and argued with the person. The point she made to prove that I gave her a $20 was that It had notches at the top and bottom where I ripped the thread out. I got my money back. ---
**Author:** ![CnoteChris](https://avatars.discourse-cdn.com/v4/letter/c/278dde/32.png) [@CnoteChris](https://boards.straightdope.com/u/CnoteChris)\ **Post date:** [June 22, 2002, 3:10pm UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286/7 "2002-06-22T15:10:01Z")
> [@](#): > > \*Originally posted by femtosecond \* > \*\*The threads are embedded into the wet pulp when the paper is made. \*\* Not according to the same special on TV that **Belrix** refers to, because I was watching it too. What they said, and show, is the paper being finished (IE, it’s dry and all) and ready to be stamped (Or however it happens) with the watermark when the thread is ‘secretly’ placed on the paper. According to the voice-over guy, the process of putting the strand into the paper took something like seven years to perfect. The point is, if what they showed on TV was accurate, it was past the point of pulp when the thread was placed into/on the paper. I’m not saying you’re wrong, just that it appears that it’s more complicated than them simply embedding it when it’s in the pulp stage. Off topic a tad, what got me curious was that watermark. Apparently it’s so secret a thing that the machine that does it is blanketed by sheets and protected by a security guard around the clock. I never knew it was _that_ complicated and/or secret a process before. ---
**Author:** ![femtosecond](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@femtosecond](https://boards.straightdope.com/u/femtosecond)\ **Post date:** [June 22, 2002, 7:26pm UTC](https://boards.straightdope.com/t/security-thread-in-dollar-bills-how/115286/8 "2002-06-22T19:26:12Z")
> [@](#): > > _Originally posted by CnoteChris_ > **What they said, and show, is the paper being finished (IE, it’s dry and all) and ready to be stamped (Or however it happens) with the watermark when the thread is ‘secretly’ placed on the paper. According to the voice-over guy, the process of putting the strand into the paper took something like seven years to perfect.** Seven years is about the time since I remember seeing perfect security threads in German Mark bills. Why didn’t you just ask us? 😃 I was referring to / summing up from this collector’s site: [bbnweb.com is for sale | HugeDomains](http://www.bbnweb.com/bbn/security.html) > [@](#): > > **Embedded Security Thread** > A high strength thread, sometimes magnetic, embedded into the paper at the beginning of the drying stage. Looks to the eye as a solid dark strip within the paper. > […] > **Segmented Security Thread** > A continuous security thread usually wide and with lettering that is added into the paper during the drying process. Once added, a special tool is used to scrape the wet paper off only above the thread, and usually in a particular pattern, thus exposing alternate areas of the embedded thread. It’s not liquid or mushy pulp, but it isn’t really dry paper yet, either. Seems the challenge here (and the secret to guard) is how to get the timing right between the thread slipping out again or not going in there in the first place. I’m not sure if every country uses exactly the same procedure, though. > [@](#): > > **Off topic a tad, what got me curious was that watermark. Apparently it’s so secret a thing that the machine that does it is blanketed by sheets and protected by a security guard around the clock. I never knew it was that complicated and/or secret a process before.** Governmental paranoia. They showed the machines on TV when the euro was introduced. It’s just a big rotating cylinder with a fine wire mesh pressing a pattern into the (semi-)wet paper. I think I remember it isn’t very durable, so you want to guard what has to be easy replaceable. And it’s one of the parts that make the money authentic. Here’s a page about how watermarks are usually done: [http://members.aol.com/ggs949/Watermark/Watermarkx.html](http://members.aol.com/ggs949/Watermark/Watermarkx.html) > [@](#): > > The watermark design is usually carved into wax first and then a copper die is made from > the wax and the finished design is then stamped into a wire mesh. Then these designs are > pressed into the paper during paper manufacture while still moist, by the wire mesh > ([dandy roll](http://members.aol.com/ggs949/Watermark/Dandy_Rollx.html)). This causes a thickening or thinning in the paper fibers. When finished the > design can be seen by holding the paper upto the light.