In this section you will find some information on the specific
characteristics of mould made paper set out in alphabetical order.
The list is not yet complete and will be expanded in the future.
Fibrous edge of the paper resulting from the division of the mould into the sheet size, which is causes
the paper to gently thin out towards the edge. The mould is divided according to the size of the sheet
before the papermaking process starts. This is the reason why deckle edges cannot be changed, added
or altered once the paper has been produced. You can feel the deckle edge because the paper is getting
thinner towards the edge and when holding it up to the light you will notice that it becomes brighter, too.
Wavy cut or torn edges are not deckle edges. Only the use of a flat mould (hand made paper) or a
cylinder mould (mould made paper) enables deckle edges to form.
Machine made papers cannot be produced with deckle edges because they originate from a completely
different production method to hand made or mould made papers.
Term for a paper manufactured by hand. The papermaker starts by dipping a mould into a vat, which is
filled with a mixture of water and fibre. By slowly lifting it up, fibres accumulate on top of the wire mesh
and form a sheet. After lifting the mould out of the vat the remaining water drains off leaving a wet
formation of fibres on top of the mesh.
Term for a hammered surface finish.
Term for a mould with a wire mesh consisting of laid lines. The structure of these lines is transferred to
the paper during the sheet formation process and can be seen by holding the sheet up to the light. As the
laid structure is part of the mould it is transferred to the wire side of hand made or mould made paper.
In contrast the laid structure of machine made paper is transferred to the felt side. This is due to the fact
that the horizontal wire of any fourdrinier machine is wove. Therefore a dandy roll must be used in order
to impress a laid structure onto the felt side of the paper.
A mould consists of a metal wire mesh, which is fixed to a solid frame. The production of hand made
paper requires a flat mould while mould made paper is manufactured on a cylinder mould.
Originating from the technique of papermaking by hand, mould made paper is often referred to as
handmade but there are distinct differences.
The mould is not held by hand but instead is replaced by a slowly rotating cylinder mould which picks up
the paper stock from the vat. The sheets are discharged onto a continuously moving felt and cylinder
dried. Nevertheless they have four natural deckle edges and genuine watermarks.
Mould made paper therefore ideally combines the uniformity of machine papers with the individual
character of handmade papers. All ZERKALL papers are Mould Made.
Machine made paper is produced on fourdrinier machines which is the most economic method of paper
production. Because the sheet formation process of a fourdrinier machine is totally different, machine
made paper does not have the characteristics of a mould made paper.
In contrast to the cylinder mould which slowly rotates inside a vat and picks up the fibres, the fourdrinier
machine sprays the mixture of water and fibres onto a horizontal wire moving at a high speed.
Due to this different production method, machine made papers do not have the specific characteristics of
hand made or mould made paper.
Adding optical brightening agents to the pulp can increase the whiteness of paper. These agents use a
physical process by transforming short wave UV radiation into visible light. Because this is goes along
with an internal heating up of the fibre structure, the permanence is affected in a negative way. Paper
containing optical brightener is more likely to turn yellow.
ZERKALL Mould Made paper is only manufactured without optical brightener.
Like any other material paper is also subject to natural ageing. The ageing process cannot be totally
prevented but extended to a period of several centuries.
The permanence of paper is affected by the choice of its raw materials. It is very important to avoid wood
containing fibres. This excludes the use of recycled fibres because post consumer waste usually is a
mix of woodcontaining and woodfree fibres.
Permanent paper can only be made from cotton fibres or chemical wood pulp with a very low lignin
content (kappa-number less than 5). During the production it is important to use neutral sizing only and
to add calcium carbonate as a buffer against acids.
The requirements for the permanence of paper are standardized. The following standards represent the
highest demands for permanent paper:
DIN ISO 9706
ANSI/NISO Z 39.48-1992.
ZERKALL Mould Made papers meet the requirements of these standards and may therefore be called
Permanence must not be mixed up with light fastness, for which separate standards apply. The
permanence of paper only refers to the unprinted sheet; there is no relationship to the permanence or
light fastness of the printing ink for which separate standards apply.
Term for a rough surface finish.
By adding neutral size during the stock preparation, the surface of the paper becomes water repellent
which allows the paper to be written on. Without sizing the surface of the paper remains to be absorbing.
Term for a smooth surface finish.
Term for a mould with a wire mesh consisting of wavy laid lines. The structure of these lines is
transferred to the paper during the sheet formation process and can be seen by holding the sheet up to
As the wavy laid structure is part of the mould it is transferred to the wire side of the mould made paper.
The wavy laid mould is a speciality of ZERKALL papers.
Whether a paper is watermarked can be judged by holding it up to the light. A translucency which then
becomes visible in the form of a name, crest, logo, or picture is called the watermark.
Watermarks have a long tradition in papermaking. They originate from a wire which is formed according
to the desired image and then mounted onto the wire mesh of the mould. Along this elevation less fibres
accumulate during the sheet formation process, so that the paper becomes thinner and therefore
translucent in the form of the watermark.
It is important to know that the watermark of hand made and mould made papers will always be on the
wire side of the paper. As it originates from the sheet formation process it is very sharp and clear.
In contrast to this, the watermark of machine made paper is on the felt side only. This is due to the fact
that the wire of fourdrinier machines do not allow the use of watermarks, so that a dandy roll has to be
used in order to impress watermarks on the felt side of the paper. They are not so sharp and clear like
hand made or mould made paper.
Term for a mould with a very fine woven wire mesh without structure. Paper, which is produced with a
wove mould shows an even opacity when being held up to the light.