Introduction

For my project I chose to create watermarks using various types of cotton pulp.  My objective was to test how the different types of pulps affected the watermark.  I used three different types of cotton pulp: denim, cotton linters and red cotton linters.  Each pulp was beaten for different time periods.  I also tested two different types of techniques, the wire watermark and the light and shade watermark.  According to Brian Queen, for a clear watermark there are several factors must be taken into account: type of fiber, its length, how it is beaten, and the thickness of the sheet of paper.  I hypothesize that highly-beaten cotton linters and the wire watermark will produce the clearest, most defined watermark.  I will visually test to see which watermark produces the clearest result, however, I will measure fibers from each pulp sample to determine the reason behind the clarity of the watermark.

Background

Watermarks are designs that are embedded into paper during the papermaking process.  Watermarks are useful because they can verify the authenticity of the documents, such as business papers, passports and bank notes, because watermarks make them harder to forge. Watermarks can be seen by holding a piece of paper up to a light source.

European papermakers first used watermarks in the 13th Century to identify the guild that manufactured the paper.   There are two types of watermarks.  The first type of watermark is a wire watermark.  This is created by sewing wire onto a wire mesh mold.  The pulp slurry is then drained through the deckle leaving an imprint in the paper.  After the paper is rolled and dried, the watermark image can be seen through the paper.  The second type of watermark is a light and shade watermark.  Light and shade watermarks are produced by pressing a relief sculpture into the wire mesh mold. When paper is cast on this type of mold, the image is both raised and sunken, which creates a light and shade design (Institute of Paper Science and Technology at Georgia Tech, 2006).

Light and Shade Watermark Mold	Wire Watermark Mold

Procedure

Materials
Papermaking
Cotton Linters
Denim Pulp
Red Cotton Linters (Beat 26 minutes, Drain 32 seconds)
Deckle Box (provided in kit)
Stirring Rod
Felts and Pelons
Roller (Filled 2 Liter Bottle)
Paper Press (provided in kit)
Blotter Paper
“Beater” Blender
Wire Watermark
40 Mesh Brass Screen
30 Gauge Brass Wire (.010” diameter)
20 Gauge Brass Wire (.032” diameter)
Light and Shade Watermark
Light and Shade Mold (provided in kit)
Drainage Time Test
Graduated Cylinder
Stand
Bottomless Tin Can
Funnel
Mesh Wire Board
Stopwatch

To create the first watermark I tested the light and shade mold provided to me in Brian Queen's Watermark
in a Box kit.  I tested all three pulps: denim, cotton linters and red cotton linters.

Light and Shade Watermark
Procedure I

1. Immerse the plastic deckle box in a bowl of warm water until the water almost reaches the top.  Pour 35mL of denim slurry into
   the deckle box.
2. Using a stirrer, gently stir the pulp using a back and forth movement.
3. Lift the deckle box from the water, keeping it level until it drains and the surface of the sheet goes dull.
4. Slowly unscrew the lid and set aside the deckle.  Push the screen up from the bottom and set aside lid.
5. Turn the screen upside down onto a damp pelon over felt.  Carefully lift the screen off the newly formed sheet.  Place another pelon and felt over the sheet and then, using the roller, roll out any excess water from the sheet.
6. Carefully transfer the pressed sheet to drying board.
7. Leave sheet to dry overnight.

Repeat these steps with cotton linters and red cotton linters.

Procedure II

1. Take 300mL of cotton linter slurry and place into “beater” blender.
2. Beat the cotton linters for 10 minutes on “puree” and remove 35mL of pulp. 
3. Using remaining slurry beat for an additional 15 minutes on “puree”. 
4. After beating is complete, remove 40mL of pulp.
5. Repeat procedure I steps 1-5.
6. Carefully transfer pressed sheet to blotter paper.  Place a second sheet of blotter paper on top of sheet.  Place this assembly into press.
7. Leave sheet to dry overnight.

Repeat steps 5-7 with red cotton linters.

After creating the Light and Shade Watermark, I created my own watermark.  Using 20-gauge brass wire, I created my watermark design.  Once this was completed, I sewed the image onto 40 mesh brass screen using 30 gauge brass wire.
After the watermark was complete, I tested the wire watermark on all three pulps.

Wire Watermark
Procedure I

1. Take 300mL of cotton linters and beat in “beater” blender for 20 minutes on “puree”.
2. After pulp is beaten, test drainage time.
3. Place 50mL of pulp in 100mL of water.
4. Set up the drainage time tester: stand, graduated cylinder, funnel, mesh wire board, bottomless can deckle.
5. Stop Volume for drainage time is 140mL.
6. Pour 150mL solution into deckle – start timer.
7. Once volume has reached 140mL stop timer.
8. Clean mesh board.
   

Repeat steps 2-8 with 300mL of denim pulp.  Beat denim pulp in “beater” blender for 10 minutes on “puree”.

Procedure II

1. Immerse the plastic deckle box in a bowl of warm water until the water almost reaches the top.  Pour
   40mL of denim slurry into the deckle box.
2. Using a stirrer, gently stir the pulp using a back and forth movement.
3. Lift the deckle box from the water, keeping it level until it drains and the surface of the sheet goes dull.
4. Slowly unscrew the lid and set aside the deckle.  Push the screen up from the bottom and set aside lid.
5. Turn the screen upside down onto a damp pelon over felt.  Carefully lift the screen off the newly formed sheet. 
   Place another pelon and felt over the sheet and then, using the roller, roll out any excess water from the sheet.
6. Carefully transfer pressed sheet to blotter paper.  Place a second sheet of blotter paper on top of sheet. 
   Place this assembly into press.
7. Leave sheet to dry overnight.
8. Repeat using 30mL of same pulp.

Repeat steps using cotton linters and red cotton linters.

Procedure III

Observations and Data

Light and Shade Watermark

Procedure I
Papermaking with Watermark

Denim Sheet	Cotton Linters Sheet	Red Cotton Linters Sheet

The shapes of all samples were affected by the drying period.  Alteration in the drying process was needed to see if the drying process was the reason for the lack of a watermark.  Also, I wanted to test how the cotton linters sample would change if I increased its beating time.

Procedure II
Papermaking with Watermark

10 Minute Cotton Linter Sheet	20 Minute Cotton Linter Sheet	Red Cotton Linter Sheet

Wire Watermark

Procedure I
Beating the Pulp

Test Drainage Time

Procedure II
Papermaking with Watermark

Weight (in grams) of Paper Samples

Since the denim produced the best watermark (both 30 and 40mL samples) I will attempt to recreate the same effect on the cotton linters. The denim weight (grams) was 1/3rd less than the cotton weight. I will reduce the cotton linter pulp to 20mL.

Comparison between Cotton Linter paper (20mL) and Denim paper (30mL) with Watermarks

Cotton Linters Sample 1	Cotton Linters Sample 2	Denim Sample 30mL

Comparison between Lengths of Fibers in each Pulp using Microscope

Cotton Linter Fibers	Denim Fibers	Red Cotton Fibers

Conclusions

Out of the three different cotton pulps, the denim pulp created the best watermark image in the group.  The denim watermarking was smooth and was embedded in the paper.  The cotton and red cotton linter pulp produced an embossment on the paper, rather than a true watermark.

The denim pulp was beaten for an additional 10 minutes on top of the original beating time. (I do not know the original beating time of the cotton linters or of the denim pulp.)  The denim slurry contained the shortest fibers, which means that the denim pulp was highest beaten pulp in the group.

After testing both types of watermarks, I found that the wire watermark produced the clearest watermark.  The light and shade watermark did not create a viable watermark that could be easily seen.  The wire watermark created the best watermark on the denim pulp.

In conclusion, my hypothesis was partially correct.  The highly beaten denim pulp produced the clearest watermark using a wire design.  As seen in the microscope, the denim pulp had the shortest fibers, which allowed the watermark to become embedded in the paper.  The longer fibers caused an embossment effect in the paper samples.  If the cotton linters were beaten for a longer duration of time they would also be able to produce a watermark.

From my experiment I conclude that any highly beaten cotton pulp will create a viable watermark. Wire watermark designs work the best for average watermarkings because it can be easily seen through the paper.

Links

Institution of Paper Science and Technology at Georgia Tech.
http://www.ipst.gatech.edu/amp/collection/museum_watermark.htm

Friends of Dard Hunter
http://www.friendsofdardhunter.org/

Conqueror: How to Watermark
http://www.conqueror.com/office_site/all-about-paper/how-to-watermark/index.asp?market=row_bc

Give Your Paper DNA: Individual Watermarks
http://www.individualwatermarks.com/

Other References

Watermark in a Box kit, made by Brian Queen, in association with Castle Paper and Press.

Acknowledgements

I would like to thank Brian Queen for creating the watermark kit which I based my project on. Also to Dr. John Bordley for his help and suggestions throughout this project.