Guides
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Demystifying the terminology used in paper making, specifying and printing.
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Paper making explained
What are the fibres in papers made of?
Pulp from wood is the most common raw material for paper making. Hardwood and softwood can both be used to make paper. Typical hardwood used in the paper industry comes from: Aspen, Birch, Beech, Eucalyptus. Typical softwood is Spruce, Pine, Fir and Larch. Some papers are made from cotton rather than wood or sometimes a mix of both. There are also other mixes, including recycled contents.
Where does the wood originate?
The Forest Stewardship Council (FSC) logo on a wood or wood based product, in our case paper, is an assurance that it is made with, or contains, wood that comes from FSC certified forests or from post-consumer waste. FSC certified forests are well managed forests, accredited only by the FSC.
What is grain direction and does it matter?
Grain direction is the direction the fibres in the paper lie. When paper is produced, fibres will tend to go in one direction or other. Short Grain is when the grain lies parallel to the paper’s short side and Long Grain is when the fibres lie parallel to the long side. Grain direction is important for many reasons. Here are a few:
1. When printing a signature bound book, the grain of the paper should be parallel to the folded edge of the signature. Mixing long and short grain paper will leave the book with uneven or stepped edges when trimmed.
2. When binding a book; Paper fibres constantly contract and expand owing to glue and moisture in the atmosphere. In the binding process it’s important to make sure the paper grain on all the pages is parallel to the book binding edge. Mixing grain direction in the pages will leave you with problems such as wavy pages or resistance to turning, the binding edge is bulky, pages may flare out, or the book closes as soon as you open it.
What are the standard sheet sizes?
The A-series consists of a set of paper sizes that are defined by the ISO 216 standard. The largest size, A0, measures one square meter. The height/width ratio remains constant (1:1.41) for all sizes. This means you get the A1 size by folding an A0 paper in two along its shortest side. Then fold the A1 size in two to get an A2 size paper, and so on… A-sizes are used to define the finished paper size in commercial printing. The B paper sizes are a bit larger than their A series counterparts and are based on the geometric mean of two consecutive A series sheets. For example, B4 is between A3 and A4 in size, and B5 is between A4 and A5. B size papers are usually used for printing so the sheet can be trimmed down to an A size. SRA series paper will also give the benefit of a trimmed edge. Your printer will be best informed to tell you which paper you need as each machine will use different sizes, and for economy some sizes are preferred by printers.
How do you know which paper is right for your project?
This is a commonly asked question. Are you designing for a brand that uses a specific colour? Can you use a coloured paper rather than reproducing the colour using ink? Do you want vibrant colours and rich blacks? A coated paper would work particularly well for colour reproduction. Do you need a paper with great opacity? A bulky, opaque paper can help with the amount of show through from one side of the paper to the next. Uncoated papers can create beautiful print results too, giving a subtle texture to print while maintaining colour reproduction. Each of our papers have information about their uses and printability. We also offer dedicated advice free of charge via our Customer Service Team and Paper Consultants. Speak to us here.
What does GSM mean?
GSM refers to the substance weight of paper, relating to an area of paper that remains constant, irrespective of sheet size, expressed as grams per square metre. Typically the higher the GSM the heavier (and generally the thicker) the paper, but this isn't always the case.
Is bulk different to GSM?
Bulk is the thickness of a paper. Many people often confuse the weight of paper with the thickness. Two papers may both weigh 150gsm, but one may be a thick style of paper containing air & bulk, whilst another paper’s fibres may be tightly packed. Both are classified as 150gsm but look and feel completely different.
Why does opacity matter in paper choice?
Opacity is a property of paper that describes the amount of light which can pass through it. Paper with a high degree of opacity doesn’t let much light pass through it, while paper with a low degree of opacity is more translucent (allowing more light to pass through). The benefit of a highly opaque paper is that it will help lessen show through when printed.
What is Lignin?
A part of the "glue" in wood, naturally occurring, that holds the cellulose fibres together. Lignin is removed in chemically cooked pulps but remains in groundwood, mechanical or semi-chemical pulps. Lignin in paper causes the sheet to fade and yellow when exposed to light. Newsprint is an example of paper containing lignin.
Why would you want to use acid free paper?
Acid free or archival paper is used to preserve other items such as textiles, photographs, paintings etc where there is already an acid content. It combats the damage non archival paper can have on such items.
What does lightfastness mean?
Lightfastness is a paper property that measures how a paper will retain its original colour, brightness, and whiteness with exposure to light. Each paper has a different lightfastness rating. The lower the ranked number, the poorer the lightfastness and in turn, the higher the number, the better.
Fibre source of paper
What is Post-Consumer Waste (or PCW)?
These are recycled fibres from papers that have previously been used in the public domain and have been recycled. The percentage of PCW content varies, and is always indicated.
What is Post-Industrial Waste (or PIW)?
These are reclaimed waste fibres from the paper-making process (often known as mill-broke) and from conversion and print processes (for example envelope trimmings and printer's offcuts). This material has never been used by a consumer. By re-using the fibre, it is diverted from landfill and incineration.
What does ECF mean?
Elemental Chlorine Free is when a paper is bleached by using chlorine dioxide, rather than an environmentally less acceptable method of bleaching.
What is TCF?
Total chlorine-free pulp is bleached without compounds such as chlorine dioxide.
Gmund Bier uses spent brewers grain in the paper making process. Take a closer look here.
What other fibres can be recovered and used in the paper making process?
You are able to add a variety of other inclusions when making paper. Commonly cotton 'rag' can be used to make a paper. The cotton comes from various sources including t-shirt offcuts. We also carry papers with spent brewers grain, fabric and wool.
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The treatment of paper prior to printing
What is a Deckle Edge?
A deckle edge is the rough, irregular edge of a sheet of paper before it is trimmed. Prior to Fourdrinier machines this edge was unavoidable. Nowadays selected papers are purposely created to have a deckle. A pisser (a high-powered jet of water) is aimed carefully at the long edge of the sheet cutting some fibres and leaving others.
What is a Fourdrinier?
A fourdrinier is a commercial size paper machine, capable of making continuous reels of paper rather than single sheets. The Fourdrinier machine is made of four sections – Forming Section /Wet End, Wet Press Section, Dryer Section and Calendar Section. The machine turns pulp which is diluted with 99% water into paper using these sections.
What is a laid paper?
In pre-mechanical paper making, the laid pattern was produced by the wire sieve used to produce single sheets of paper. Nowadays, in mechanical paper making a laid paper is simulated by using a dandy roll to mimic the linear pattern of a traditional laid paper.
What is a Dandy roll?
A dandy roll is a wire-covered roller that rides on a paper machine to compact the sheet and sometimes impress a watermark if a design has been added to the wire roll.
What does sapphire treating mean?
Sapphire Coating is used to treat paper to improve printing on a HP Indigo digital press. The process allows the ink to adhere better to the paper. Sapphire Coating allows HP Indigo presses the ability to make any paper suitable for their HP Indigo press to use. We can sapphire treat our papers in house.
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The printing process
How do you know which print process is right for your project?
There are lots of print processes available, from commercial printing processes designed for thousands of copies of a job, to unique digital printing designed to offer small quantities with the possibility of personalisation. Budget is usually the deciding factor, however each print process has it’s own unique qualities which may lend itself to a specific project.
What is the different between litho (offset) and digital printing?
Offset Lithographic printing uses plates, usually made from aluminium, which are used to transfer an image onto a rubber “blanket”. That image is then rolled onto the paper. It's called offset because the ink is not transferred directly onto the paper. Litho presses run very efficiently once they are set up, making it the best option when larger quantities are needed. Digital printing doesn't use plates, but instead uses options such as toner, or larger printers use liquid ink. Digital printing is beneficial when lower quantities are needed, even as low as one copy. Another benefit of digital printing is it's variable data capability: if each print needs a unique aspect such as a code, name, or address then digital is the right choice. Offset printing cannot accommodate this variation.
What is a flyleaf?
A flyleaf is the blank page at the beginning and end of a book.
What is a dummy?
A dummy is a model/mock up. Printers and designers use dummies to help see how a print project will look when it is complete. A dummy is a print prototype that helps physically visualise the project. It’s useful to determine weights, sizes and format. We create dummies free of charge for your projects.
What is Screen Printing?
A printing technique, using a 'screen mesh' to transfer ink onto paper. The ink is spread using a blade or squeegee, and a reverse stroke causes the screen to touch the paper momentarily transferring the ink. A stencil blocks areas to stop the ink transfer creating a desired result. One colour is printed at a time, so several screens can be used to produce a multicoloured image or design. Traditionally, the process was called silkscreen printing because silk was used in the process.
What is Letterpress printing?
The movable type is laid into a printing press and inked. Paper is then pressed to transfer the ink to the paper. Letterpress was the primary printing method for hundreds of years before the invention of offset printing in the 20th century.
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Finishing processes on paper
What does die mean in the paper and print industry?
A die is a metal tool used in printing to cut or add a specialist finish to paper mostly using a press. Like moulds, dies are customised to the item they are used to create. A die would be custom made for artwork that would be either: embossed, de-bossed, die cut or hot foiled.
What is the difference between emboss and deboss?
An embossing is raised, while a debossing is sunken into the surface of the paper. Dependent on what paper you emboss or deboss into, the reverse side of the paper might protrude somewhat.
What is a blind embossing?
Blind embossing is the method of creating raised artwork without the use of ink or foil. Typically, two metal dies are used for this process: one with a raised artwork (male), and another with matching but recessed (female) artwork. The die is pressed into the paper creating a raised impression.
What is foiling?
The design to be reproduced in foil is made into a metal die. The die is heated up, and the foil is placed between the die and the paper to be stamped. When the die is applied to the surface of the foil & paper, the foil bonds to the paper, producing the metallic effect.
What is the difference between die-cutting and kiss-cutting?
Kiss cutting is used for making adhesive labels/stickers. Unlike die cutting, kiss cutting does not penetrate the backing material.
What is engraving?
Often referred to as ‘die stamping’, ‘copperplate’ or ‘intaglio’ Die stamping involves the production of either a machine etched or a hand engraved die. This ‘female’ die is then mounted onto a large die stamping press where it is inked. The excess ink is wiped off the surface of the die, leaving only the ink within the engraved image. It is then pressed under extreme pressure over a ton per square inch onto the paper. This process produces a beautiful raised, 3D image of incredible clarity and quality.
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