# How is paper made? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [November 22, 2005, 4:33pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265 "2005-11-22T16:33:20Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [November 22, 2005, 4:33pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/1 "2005-11-22T16:33:20Z")
[http://www.straightdope.com/mailbag/mpapermaking.html](http://www.straightdope.com/mailbag/mpapermaking.html) > [@Una](#): > > Plants used for papermaking include cotton… acid is used to modify the chemical structure… So if I got some cotton, and mixed it with nitric and sulfuric acids… 😃 Actually, I had a question about getting the paper off of the mats: > [@Una](#): > > The pulp is highly diluted with water (sometimes 99%-plus), and the mixture is sprayed onto a moving mesh screen in layers to make a mat. It’s like spraying multiple layers of paint to produce a thicker coat. The mat then goes through several mechanical and vacuum processes to dewater, compact, and dry it, and then is sent through heated rollers to squeeze out any remaining moisture and compress the mat into paper. Infrared dryers may be used to speed up the process or achieve a more consistent product. The mat can be quite large, as wide as 10 yards, and is generally laid out as a long, continuous roll–according to the German Pulp and Paper Association, the sheets can end up in a continuous roll 60 kilometers in length! I’ve seen people make paper using DIY kits. They dip their screens in the solution and allow it to dry. When the paper is dry, they peel it off of the mat. At what point in the commercial paper-making process does the paper come off of the mat? After going through the rollers? Paper looks like it has the same texture on both sides. If a roller compresses the paper on the mat, wouldn’t the mat-side have a rougher texture? _Does_ it have a rougher texture, and I just haven’t noticed? How does the paper get off of the mat? I imagine an large ‘conveyor belt’ where the dried paper is drawn up a ramp while the mat belt makes a one-eighty and goes back to pick up another coat. ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [November 22, 2005, 5:04pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/2 "2005-11-22T17:04:07Z")
> [@Johnny L.A.](#): > > [http://www.straightdope.com/mailbag/mpapermaking.html](http://www.straightdope.com/mailbag/mpapermaking.html) > > So if I got some cotton, and mixed it with nitric and sulfuric acids… 😃 > > Actually, I had a question about getting the paper off of the mats: > > I’ve seen people make paper using DIY kits. They dip their screens in the solution and allow it to dry. When the paper is dry, they peel it off of the mat. At what point in the commercial paper-making process does the paper come off of the mat? After going through the rollers? Paper looks like it has the same texture on both sides. If a roller compresses the paper on the mat, wouldn’t the mat-side have a rougher texture? _Does_ it have a rougher texture, and I just haven’t noticed? How does the paper get off of the mat? I imagine an large ‘conveyor belt’ where the dried paper is drawn up a ramp while the mat belt makes a one-eighty and goes back to pick up another coat. In the article, the term “mat” refers to the pulp itself; the pulp is spread onto the screen and becomes a mat. I’ll leave it to the expert to answer your questions, but I’d speculate that the mat can be removed from the screen once it’s dried, and maybe the screen and mat go between rollers together at first. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [November 22, 2005, 5:06pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/3 "2005-11-22T17:06:13Z")
> [@Nametag](#): > > In the article, the term “mat” refers to the pulp itself… I must have mis-parsed. ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [November 22, 2005, 5:12pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/4 "2005-11-22T17:12:22Z")
I hope we can lure \*\*Una \*\* in here to answer a few questions. I was wondering about the old use of rags. I assume that was for the cotton content but I was wondering is she could provide more information on it. Great article **Una** Jim ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [November 22, 2005, 6:05pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/5 "2005-11-22T18:05:38Z")
Im from the Fox River Valley (between Lake Winnebago and Green Bay) a place that has quite a bit of paper making. Thilmany (now part of International paper) has co-located pulp and paper plants. On the south side of Kaukauna it USUALLY didn’t stink too bad, but once and a while - phew!. And if you left the area it took a while to re-acclimate. I should point out that a lot of trees for paper is grown just like any other crop (e.g. corn), and the paper making isn’t destroying forests continueously. My brother studied paper chemisty, but I don’t know a lot about it. Brian ---
**Author:** ![A.R.Cane](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@A.R.Cane](https://boards.straightdope.com/u/A.R.Cane)\ **Post date:** [November 22, 2005, 6:07pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/6 "2005-11-22T18:07:24Z")
I worked in a paper mill as a kid some 50 years ago. It was a recycling plant that turned out a heavy brown product which, as I recall was used in making corrugated cardboard for boxes and other uses. I started on the vat where the recycled paper was mixed with water and turned into a slurry. This was like a giant mixer and was a pretty dangerous place to work. It’s been a long time, but I think the erntire machine was over 100’ long. The slurry was sprayed onto the conveyor and squeezed, dried and then trimmed until it exited the machine on to a roller. A finished roll was about 5-6’ wide and about the same height when it was cut (torn manually) and started on a new roller. I worked that end of the machine also. The stench was somewhat foul, but within a few minutes of arriving at work you didn’t notice it anymore. Of course when you went home each day you reeked of the odor and everyone else could smell it. ---
**Author:** ![AncientHumanoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ancienthumanoid/32/278_2.png) [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)\ **Post date:** [November 22, 2005, 6:16pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/7 "2005-11-22T18:16:01Z")
Great report, Ma’am. Hey, she can be funny, sci-fi-y weird, and even a little grumpy at times, but when **Una** submits a report, it’s darn accurately researched. Even to the point of submitting drafts to others (no, not me) for review. **Una** , you should host a site of your own. We now end the suck up looking (it’s not, really) post and return you to your regular sad lives. 😉 ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [November 22, 2005, 6:43pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/8 "2005-11-22T18:43:53Z")
Guess I spoke too soon. Thilmany WAs part of IP, but some of the plants got bought: [http://www.thilmany.com](http://www.thilmany.com) Brian ---
**Author:** ![jpu1](https://avatars.discourse-cdn.com/v4/letter/j/e9bcb4/32.png) [@jpu1](https://boards.straightdope.com/u/jpu1)\ **Post date:** [November 22, 2005, 9:08pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/9 "2005-11-22T21:08:23Z")
The paper says “Bleaching typically uses some combination of chlorine, sodium hydroxide, and hydrogen peroxide as whitening agents or lignin removers. Pulp and paper mills used to be a significant source of chlorine, dioxin, and other hazardous emissions, so many have switched from pure chlorine to chlorine dioxide, and some have eliminated chlorine entirely.” This statement is somewhat outdated, at least for mills in the U.S. No bleached kraft mill in the U.S. uses any elemental chlorine for pulp bleaching anymore, and few if any mills of any type use it for that purpose. The reason the paper does not have the impression of the forming wire on one side is that it leaves the wire while it is still quite wet and is, from then on, pressed in various ways on both sides. Any pattern left by the wire quickly disappears. Old rags are, indeed, used as a source of cotton fiber. In fact, old blue jeans are a prominent part of the fiber source for currency paper. Acid is not used to process the rags, however. Heat and some caustic are used in a mechanical agitator to break up the cloth into fibers useable for papermaking. ---
**Author:** ![jpu1](https://avatars.discourse-cdn.com/v4/letter/j/e9bcb4/32.png) [@jpu1](https://boards.straightdope.com/u/jpu1)\ **Post date:** [November 22, 2005, 9:11pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/10 "2005-11-22T21:11:42Z")
The paper says “Bleaching typically uses some combination of chlorine, sodium hydroxide, and hydrogen peroxide as whitening agents or lignin removers. Pulp and paper mills used to be a significant source of chlorine, dioxin, and other hazardous emissions, so many have switched from pure chlorine to chlorine dioxide, and some have eliminated chlorine entirely.” This statement is somewhat outdated, at least for mills in the U.S. No bleached kraft mill in the U.S. uses any elemental chlorine for pulp bleaching anymore, and few if any mills of any type use it for that purpose. The reason the paper does not have the impression of the forming wire on one side is that it leaves the wire while it is still quite wet and is, from then on, pressed in various ways on both sides. Any pattern left by the wire quickly disappears. Old rags are, indeed, used as a source of cotton fiber. In fact, old blue jeans are a prominent part of the fiber source for currency paper. Acid is not used to process the rags, however. Heat and some caustic are used in a mechanical agitator to break up the cloth into fibers useable for papermaking. ---
**Author:** ![jpu1](https://avatars.discourse-cdn.com/v4/letter/j/e9bcb4/32.png) [@jpu1](https://boards.straightdope.com/u/jpu1)\ **Post date:** [November 22, 2005, 9:14pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/11 "2005-11-22T21:14:12Z")
I agree with other commenters that this is a well researched article. I just have one bit of updated information. The article says “Bleaching typically uses some combination of chlorine, sodium hydroxide, and hydrogen peroxide as whitening agents or lignin removers. Pulp and paper mills used to be a significant source of chlorine, dioxin, and other hazardous emissions, so many have switched from pure chlorine to chlorine dioxide, and some have eliminated chlorine entirely.” This statement is somewhat outdated, at least for mills in the U.S. No bleached kraft mill in the U.S. uses any elemental chlorine for pulp bleaching anymore, and few if any mills of any type use it for that purpose. The reason the paper does not have the impression of the forming wire on one side is that it leaves the wire while it is still quite wet and is, from then on, pressed in various ways on both sides. Any pattern left by the wire quickly disappears. Old rags are, indeed, used as a source of cotton fiber. In fact, old blue jeans are a prominent part of the fiber source for currency paper. Acid is not used to process the rags, however. Heat and some caustic are used in a mechanical agitator to break up the cloth into fibers useable for papermaking. ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [November 22, 2005, 9:18pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/12 "2005-11-22T21:18:05Z")
Thank you **jpu1** , I always heard about rags in the process. Not sure about the triple post, sometimes the board takes a long time to update and you may have hit Submit 2 extra times. Jim ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [November 22, 2005, 10:06pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/13 "2005-11-22T22:06:06Z")
> [@jpu1](#): > > Old rags are, indeed, used as a source of cotton fiber. In fact, old blue jeans are a prominent part of the fiber source for currency paper. Acid is not used to process the rags, however. Heat and some caustic are used in a mechanical agitator to break up the cloth into fibers useable for papermaking. Thus giving us the classic rags to riches story!!! 😛 ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [November 22, 2005, 10:07pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/14 "2005-11-22T22:07:08Z")
Um, by the way, as usual, great job, **Una**!!! ---
**Author:** ![nd\_n8](https://avatars.discourse-cdn.com/v4/letter/n/439d5e/32.png) [@nd\_n8](https://boards.straightdope.com/u/nd_n8)\ **Post date:** [November 22, 2005, 11:31pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/15 "2005-11-22T23:31:05Z")
> [@jpu1](#): > > The reason the paper does not have the impression of the forming wire on one side is that it leaves the wire while it is still quite wet and is, from then on, pressed in various ways on both sides. Any pattern left by the wire quickly disappears. My first day here and I see a post I have experience with 😃 jpu1 is right, the web pattern is pressed out by various pressure rolls while the web is still quite wet (but dry enough to lift off of the webbing). Usually an air curtain lifts the web from the belt and into the rollers. The shmooshier it is the smoother the finish will be on the web side, usually the top comes out pretty smooth anyway. However, being shmooshy means the web is quite fragile, the dryer it is the faster the mill can run (even the shmooshy stuff runs pretty fast). So, drier web = faster runs = cheaper paper = more likely to be able to tell the difference between the web side and the finished side. eg. look at both sides of a kraft paper grocery sack, the inside is much coarser. It is basically the same for all paper, clay coatings aside, all paper has a coarse side and a smooth side. This is not important unless the paper is used for printing. Printing on the web side tends to get a little fuzzy, which again is not important unless printing in more than one color (using rosettes). I can go into more detail about that if anyone is interested, but the short story is, on a standard ream of bond paper, the label usually tells which side to print on with the best results and thus which side is the finished side and which is the web side. Good luck trying to figure it out yourself, it is almost impossible to see with the naked eye, not nearly as easy as a kraft sack. And they said I’d never get anywhere working in a box plant. 😉 ---
**Author:** ![Billdo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/billdo/32/315_2.png) [@Billdo](https://boards.straightdope.com/u/Billdo)\ **Post date:** [November 23, 2005, 12:12am UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/16 "2005-11-23T00:12:58Z")
Great report as usual. I do have a follow-up question, however. What is a watermark, and how do they put them into paper? ---
**Author:** ![nd\_n8](https://avatars.discourse-cdn.com/v4/letter/n/439d5e/32.png) [@nd\_n8](https://boards.straightdope.com/u/nd_n8)\ **Post date:** [November 23, 2005, 1:05am UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/17 "2005-11-23T01:05:31Z")
[awww my shnookie is so smart i love u bunches 🙂 jpu1 is right, the web pattern is pressed out by various pressure rolls while the web is still quite wet (but dry enough to lift off of the webbing). Usually an air curtain lifts the web from the belt and into the rollers. The shmooshier it is the smoother the finish will be on the web side, usually the top comes out pretty smooth anyway. However, being shmooshy means the web is quite fragile, the dryer it is the faster the mill can run (even the shmooshy stuff runs pretty fast). So, drier web = faster runs = cheaper paper = more likely to be able to tell the difference between the web side and the finished side. eg. look at both sides of a kraft paper grocery sack, the inside is much coarser. It is basically the same for all paper, clay coatings aside, all paper has a coarse side and a smooth side. This is not important unless the paper is used for printing. Printing on the web side tends to get a little fuzzy, which again is not important unless printing in more than one color (using rosettes). I can go into more detail about that if anyone is interested, but the short story is, on a standard ream of bond paper, the label usually tells which side to print on with the best results and thus which side is the finished side and which is the web side. Good luck trying to figure it out yourself, it is almost impossible to see with the naked eye, not nearly as easy as a kraft sack. And they said I’d never get anywhere working in a box plant. 😉 [/QUOTE] ---
**Author:** ![Moirai](https://avatars.discourse-cdn.com/v4/letter/m/96bed5/32.png) [@Moirai](https://boards.straightdope.com/u/Moirai)\ **Post date:** [November 24, 2005, 4:20pm UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/18 "2005-11-24T16:20:00Z")
Excellent report as usual, **Una**. Does anybody around here (members OR staff) really appreciate you guys enough? The SDSTAFF write some of the best stuff I have read on the 'net. Apart from the Master, of course… I am curious about the watermark as well- it looks like a last-minute add to the finished paper? And does the watermarking process differ with different paper content (wood vs. cotton)? ---
**Author:** ![CurlyD](https://avatars.discourse-cdn.com/v4/letter/c/ee7513/32.png) [@CurlyD](https://boards.straightdope.com/u/CurlyD)\ **Post date:** [November 26, 2005, 2:40am UTC](https://boards.straightdope.com/t/how-is-paper-made/332265/19 "2005-11-26T02:40:00Z")
The watermark is made by a dandy roll. Here’s a description of the process from [MeadWestvaco.](http://www.meadwestvaco.com/packaging.nsf/v/glossaryVY) > [@](#): > > **Watermark** - The impression of a design, pattern or symbol in a sheet while it is being formed on the paper machine wire. It appears in the finished sheet as either a lighter or darker area than the rest of the paper. A shaded watermark (aka intaglio watermark) is produced by a dandy roll located at or near the suction box on the paper machine. > > The desired design is pressed into the wire covering the surface of the dandy roll similar to an intaglio engraving. As the wet pulp moves along the web, the dandy roll presses down and creates an accumulation of fibers, thus the watermark is seen as being darker than the rest of the sheet. A wire mark is accomplished by impressing a dandy roll with a raised surface pattern into the moving paper web in a similar manner to the shaded mark. This creates an area with less fiber, making it lighter and more translucent. [Here](http://www.aerogramme.com/General/Watermarks.html) is a description of how a dandy roll is made, along with a couple of pictures.