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All About Watercolor Paper

Materials

Papyrus paper
Papyrus from the Book of the Dead of Nedjmet

Perhaps from the Royal Cache at Deir el-Bahari, Egypt
21st Dynasty, around 1070 BC

Pulp

We all know watercolor paper is usually cellulose, which is some type of plant fiber chopped up, soaked in water, smoothed and pressed into paper. Very simple and humans have made paper from around 2400 B.C., starting with papyrus for the cellulose. But what kind of cellulose and how it's processed matters a great deal to the artist.

Watercolor paper is usually made from cotton rag and linters. These can be new fibers or recycled from old fabrics. Cotton or linen is 10 times stronger than wood fibers and naturally acid free. Cotton rag can be old fabrics (I'm sure the handmade Indian paper I love is made from old sheets or something!). Or rags can be made from new fabric scraps leftover from clothes manufacturing. Cotton rag is the name for the long fibers collected in a cotton gin that can be woven into fabric. Recycling fabric into paper is one of the oldest forms of recycling there is! Cotton rag is very flexible so paper won't tear easily.

Cotton linters is made from the shorter fibers still attached to the seeds after initial processing. This used to be waste material since it was hard to separate from the seeds, so it's good we can use every bit of the cotton now. Linters is weaker than the long cotton rag fibers, so it should be mixed with cotton rag at least.

Stronger watercolor paper will be made with more cotton rag than linters. Student grade papers will be made with more linters than rag.

Linen can also be used in watercolor paper. Linen fibers are very long and strong, so they're useful for a very translucent strong paper. They're also not quite so water permeable - and neither is the paper that is made from them.

Don't forget wood pulp. A lot of sketchbooks and cheaper paper are made from wood pulp. It's one reason most sketchbooks are only good for one wash. You go back for another wash or try to scrub an area and the paper disintegrates! "Acid free" and lignin free wood pulp is called alpha cellulose. Lignin is basically plant glue that repels water - so not what watercolorists want! Acid free paper is generally good for about 60-80 years without yellowing.

An easy way to tell if your wood pulp paper is relatively acid free is a burn test. If the ash is black, it has lignin in it so it's not archival. If it's white, it's lignin free and archival.

Sizing

Sizing should always be used for watercolor paper. It coats the fibers to help them resist the paint and water. There's a fine line between so much sizing the paper resists paint, beading up - think bristol board. Or so little sizing it's like painting on a sponge - newsprint. Unsized paper is called waterleaf. Good watercolor has just the right amount. Enough sizing that the color doesn't seep everywhere, not so much that the paint doesn't flow.

Think of sizing as a protective coating on each fiber. It adds strength, retards oxidation, and helps the paper keep its shape. Sizing can be internal, dipped in the pulp vat, or external, the paper sheet dipped after it's formed and dried.

External sizing is more time consuming, but allows for more control over each sheet. External sizing can be sprayed on, brushed on, or dipped. Dipping is considered the best method since the sizing soaks into the paper a little bit. Think of sizing as a glue coating your paper and allowing you control over your paint.

Gelatin, made from animal hides, is the best sizing for watercolor paper. Gelatin has been used from at least 1276 at the Fabriano paper mill.

Alum or Aluminum sulfate (well known to gardeners) has been used since the 16th century to help stabilize and preserve the gelatin and make it easier to work with.

Some cheaper watercolor papers contain fillers and brighteners, such as kaolin. These can completely throw off your painting when they mix with your paints. If you can't get clear colors, first check your paints, then your paper!

Papermaking

Beating

Beating the fibers with a Hollander beater makes much stronger paper. The long fibers interlock and absorb water, creating more chemical bonds between the fibers. Fibers that haven't been beaten are soft and spongy, such as blotter paper. You can make blotter paper in your blender, but chopping is not the same as beating. Chemically softening the fibers to make paper is also not the same thing. A very well beaten paper example is a dollar bill, strong and almost translucent. Watercolor paper is not as strong as a dollar bill, but not newsprint either. Watercolor paper is usually beaten from 1-4 hours, depending on the fiber and the manufacturer.

Moulding the Paper

Machinemade Paper

This completely automated process injects pulp onto a mesh cylinder, then the paper is pressed between felts, dried by hot rollers, and cut and dried.

Machinemade paper is a modern wonder that allows us to have cheap sketchbooks and everything else. But it's not really the same thing as the feel of quality paper.



Mouldmade Paper

Paper mill
St Cuthbert's Mill, paper on cylinder
Saunders Waterford Paper is made here.
The machine mouldmaking the paper
is about 100 years old.

Pulp is pressed onto wire cylinders, then rolled onto a felt conveyor belt and dried. There are not many watercolor cylinder mould machines left in the world.

Mouldmade paper can only have 2 deckle edges, naturally formed on the cylinder sides as the paper is made. The other 2 "deckles" on mouldmade paper are usually cut with a water jet.

Since mouldmade paper is pressed between cylinders to form it, it always has a grain the paper is pressed in. This grain affects how your paint flows over the paper. A directional grain means the paper is weaker in the other direction since fibers don't interlock as firmly as traditional paper.







Handmade Paper

handmade paper
Encyclop9die, Papermaking, before 1772

Handmade paper is a rare and beautiful thing. Handmade is an often misused term now since it is so rare. Many companies claim to have handmade paper when what they manufacture is mouldmade paper that is hand inspected and separately dried. That's not a bad thing, but it is a very different thing to the artist. The texture of handmade watercolor paper cannot be duplicated.

In the handmade process, there are two frames, a mould covered with mesh and the deckle frame. The frames are dipped in a pulp vat where pulp is moved back and forth and side to side. This unique action means that the fibers in handmade paper are interwoven completely. It makes the paper ideal for the watercolorist since it's very strong and very even. The pulp is layered and moved until precisely even and the correct level.

How to make handmade paper
The paper is moved back and forth in two directions by the papermaker so handmade paper has no directional grain.







Next, the paper is couched or rolled off onto felt to start drying. It is alternately pressed and air dried in a loft, depending on the finish required. Air drying slowly is important since it gives a beautiful texture to the paper. After drying for a time, the paper is dipped in sizing, then air dried again.

Only handmade paper has four real deckled edges. Since they are so beautiful, I rarely cut a handmade sheet of paper. Instead I order handmade paper in multiple sizes and choose the best size for a painting. The finished painting can be framed to show the deckle edges.

Anyone can make a sheet of paper. Almost no one is left who can make consistently good sheets of paper. It's a dying art, kept alive by a few companies like Twinrocker, Garza Papel, and St. Armand.



Drying

After the initial wicking away of enough water to move the paper, paper used to be hung to dry naturally in the sun. This bleached it without chemicals. I have not heard of any company still hanging paper outside to dry in the sun but there are many companies (handmade and mouldmade) that still hang paper to dry in climate controlled rooms.

The best handmade or mouldmade paper is individually hung to dry very slowly in a damp environment. This creates a wonderful texture. Other sheets are air dried together in small bundles, which smooths the texture.

Modern drying is done on hot cylinders as the paper is being made.

Traditional drying methods take weeks but leave a texture and workable surface that can't be duplicated.





Watercolor Paper Weights and Sizes

You'll often see papers labeled with 90#, 300#, etc. With watercolor paper. The two weights you'll see the most often are 140# (300gsm) and 300#.

One Ream or 500 full Imperial sheets (22" x 30") 140# paper weighs 140 pounds.

22" x 30" 140# 300gsm
22" x 30" 200# 400gsm
22" x 30" 250# 460gsm
22" x 30" 300# 640gsm
29" x 40" 260#
(same paper weight
as 22" x 30" 140#)
356gsm


Quarter Imperial Sheet 11" x 15" 27.9cm x 38.1cm
Half Imperial Sheet 15" x 22" 38.1cm x 55.9cm
Royal 20" x 25" 51cm x 64cm
Super Royal 20" x 28" 51cm x 71cm
Full Imperial Sheet 22" x 30" 55.9cm x 76.2cm
Elephant 26" x 40" 64cm x 102cm
Double Elephant 29" x 40" 69cm x 102cm
Triple Elephant or Emperor 40" x 60" 102cm x 152cm

From the base of a full sheet, paper sizing is fairly standard. An Imperial sheet (usually called full sheet) is the most common base size. Once you're into elephant sizing, it starts to vary an inch or 2 by country and manufacturer. Perhaps it was originally judged by a real elephant ear size!

Remember, after the standard weight of 140# paper using the size 22" x 30", paper weights get complicated. A double elephant (29" x 40") may be 260# paper, but that is the same weight paper as 22" x 30" 140# paper.

If you want larger paper, Arches, Strathmore and Saunders Waterford offer rolls approximately 60" x 10 yards. Watercolor rolls are generally 140# paper. It's a cost effective way to paint if you stretch your paper and know you like a surface!

No matter how tempting, you really don't want to use less than 140# paper for watercolor paintings. That's the limit weight for where you can do multiple washes and be able to scrub the paper some. Lighter weights, while they are marked "watercolor" will start to peel up in clumps with the second wash. They will buckle even when stretched.

Your painting time is too precious to waste on paper that a good painting is almost impossible on!



Watermarks

Watermarks in Papermaking Watermark Image
An elaborate light and shade watermark and
the mold for it at Robert C. Williams Paper Museum

A watermark is a manufacturer's mark that can be seen when the paper is held up to the light. It helps identify the paper later, when museums are checking your work for what you used! A watermark symbol is sewn onto the screen the pulp rests on. The wire of the mark is completely coated by pulp, which is why a subtle one can't be seen at all until the paper's backlit. A more prominent watermark, like Twinrocker's, can be felt and seen without backlighting.















It's important to note this information is on European and American watercolor paper because that is what I paint on and know well. I love the beauty of Asian papers but I haven't painted many paintings on them yet.

Of course, I love exploring new materials and techniques, so hopefully I will have Asian type papers on here someday!