Digital print is one of the most common ways to print. It is also one of the cheapest options because it does not require as much preparation as some other processes. Digital print is usually used for smaller print runs (up to 500 sheets) as it does not have as a high print quality as Lithography does (page 17). There are many different sizes of digital printer but the largest is up to A0 (Page 69) The printer on the right can print up to any length until the roll of paper runs out. It is also fitted with a built in trimmer to cut the paper when the design has been printed.
Process:
With digital print there are two different processes which we can go through. The first is Inkjet printing which uses CMYK inks. These printers are the more common home/school printers which you will probably use. The second way to print is using a Laser printer. This does not use ink it uses toner. This process is slightly different to an Inkjet printing as it involves a laser beam passing over a charged drum which defines the image. The drum then selectively collects the correct colour toner and transfers the image to paper.
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Litho Print:
Lithography or Litho print requires several aluminium plates in order to print designs. A design which is to be printed using Litho must be split into different colours or inks before it is sent to the printers. Each of the colours requires an individual plate. Each plate will travel through a machine (see left) where it will be coated with the ink colour and printed on the paper, card etc. The colours will be layered up on top of each other to create the final image. Litho print is a cheaper alternative to digital print as it allows for much larger quantities to be printed at once. Plates can also be stored away for future print runs.
Process:
The process of Lithography is based on the principle that oil and water don’t mix. In order to print using lithography a design must be prepared onto an aluminium plate (see left). A plate is made by etching a design into it. This is done by firstly printing the design onto the plate using a polymer (oil based) material, this is then coated with a chemical solution which will etch the design into the plate. The process of etching creates a raised area where the ink will be contained. The ink is added to the plates through a variety of rollers. The plates are dampened, first by water rollers, then ink rollers. The ink gets to the plate from the ink fountain which will be filled the intended colour. The image area of the plate picks up ink from the rollers. The water rollers keep the ink off of the non-image areas of the plate. Each plate then prints its image to a rubber blanket which then prints the image to the paper. The plate itself does not actually touch the paper, this is called offset lithography.
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Silk Screen Printing:
Silk screen printing can be done on a large scale but it can also be quite small and bespoke print runs. The majority of products which come out of silk screen printing are road signs. They are produced at a large scale with very specific machinery which allow it to work much quicker. For smaller bespoke screen printing such as handmade cards and gig posters the machinery is much smaller and requires a lot of work from humans.
Process:
- A Silk Screen is selected depending on the size of the print.
- The design is printed off onto clear acetate which will make it easier to expose the design onto the screen.
- Screen is coated in green emulsion which will allow the design to be transferred onto the screen for printing.
- The screen is then taken to an exposure unit which uses a powerful UV light to expose the acetate design onto the screen.
- The screen is then rinsed off so that the design is all that is visible.
- The screen is then clamped into a screen printing bed. Paper is placed on the bed underneath the screen.
- A collection of ink is then placed at the top of the screen ready for printing.
- A squeegee is then used to pull the ink over the screen which will press through the tiny holes to the paper underneath. The screen will print as many times as you wish as long as there is enough ink.
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Flexography:
Flexography can be used to print on materials such as cellophane, polythene and metallic films, so it is often used to print plastic shopping bags. It is also used to produce milk cartons, plastic carrier bags, disposable cups, labels, envelopes, newspapers and wrappers. It is the cheapest way to print publications and packaging in large quantities.
Process:
Flexography is very similar to litho print, it uses plates, unlike Litho though Flexography uses a rubber plate instead of an aluminium plate. There are many different ways to produce a plate for Flexography but the most recent is called Laser engraving. This involves a laser cutting into the plate to create a raised area in the shape of the design. Ink is transferred onto the raised areas and a doctor blade is used to remove the excess ink. The paper/material is then sandwiched between the plate and the impression cylinder to transfer the image. The design is then passed through a dryer before it can be touched.
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Gravure Print:
In gravure printing, the image is made up of small holes sunk in the surface of the printing plate. The holes are filled with ink and any excess is removed. Paper comes into contact with the ink in the holes when it is pressed against the plate. Gravure printing is used for long, high-quality print runs such as magazines, mail-order catalogues, packaging, and printing onto fabric and wallpaper. It is also used for printing postage stamps and decorative plastic laminates, such as kitchen work tops.
Process:
Like Litho and Flexography print Gravure print also uses plates and rollers to print an image. In this case the image is transferred to the plate by a laser which creates small holes in the shape of the design which contain the ink, like flexography the excess ink is removed by a doctor blade so the design is not saturated with too much ink when it is printed. The plate is then rolled around the plate cylinder onto a pice of paper/material which is sandwiched between the plate cylinder and the impression cylinder.
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Pad Print:
Pad printing is a great way to print onto small, awkward shapes and also a variety of materials. There is a wide selection of inks which have been developed for pad printing and it has become very popular. The process is very simple and can be done with large industrial machines as well as manually at home or school.
Process:
Like other print processes in order to pad print a plate must be used. The design is etched into a plate which is then covered with ink, a doctor blade scrapes off the excess ink so that all is left is the raised area which has a layer of ink. The ink which is used evaporates and becomes tacky which is what will stick to the silicone pad. The pad will e lowered to the plate and the tacky ink will stick to it, the pad is then moved to the object which is going to be printed and is pressed to it. Because the pad is silicone the ink comes off on the object perfectly without the pad needing to be cleaned for the next use.
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Embossing:
Embossing is the impression of an object onto another which creates a raised outline. Like the image on the left embossing makes for a very high quality finish on print jobs. It is usually only used for the cover of a publication or a specific type of branding such as a business card. It is an expensive process as it requires a copper plate to be engraved with a design. Unlike the printing plates copper plates take several hours to make and require constant attention in order to make sure it does not over develop.
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Debossing:
Debossing is the opposite of Embossing, instead of the design being raised out of the paper it is indented into it. The process of this is very similar to embossing though it does work with a wooden plate which can be laser cut, this is a much quicker and cheaper option to develop and has a great effect on a piece of artwork.
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Foiling:
Foiling is another popular process which can make a design look extremely high quality. Foiling involves the design being stamped on the material through a metal foil this forces the foil into the surface of the material and adds a great final effect to a design. There are many different colours of foil
which can be used and it can be done on a wide range of materials, not just paper.
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Die Cut:
Die cutting is used to make multiple, identical shapes. It works in a similar way to a biscuit cutter. A shaped blade called a die is used to cut material. The material to be cut is placed under the die and the die is lowered. For creasing, blunt blades are used. The blade does not cut through the material but creases it. This is useful for materials that need to be folded such as packaging and publications.
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Laser Cut:
Laser cut is a great way to make quick stencils and debossing plates from wood. It involves a high powered laser cutting a design into a material. There aren’t many limitations when it comes to material choice as it can cut through almost anything. The process is very time consuming as it can only cut one design at a time, unless on a very large commercial printer in a specialist factory.
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A Formats:
A formats are the most commonly known to the general public. The size of paper in A format varies quite significantly with the largest being A0.
The Dimensions:
A0 - 1189 x 841 mm
A1 - 841 x 594 mm
A2 - 594 x 420 mm
A3 - 420 x 297 mm
A4 - 297 x 210 mm
A5 - 210 x 148 mm
A6 - 148 x 105 mm
A7 - 105 x 74 mm
A8 - 74 x 52 mm
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B Formats:
B format is more commonly used by people within the print community. They are very similar to A formats though they are slightly larger.
The Dimensions:
B0 - 1414 x 1000 mm
B1 - 1000 x 707 mm
B2 - 707 x 500 mm
B3 - 500 x 353 mm
B4 - 353 x 250 mm
B5 - 250 x 176 mm
B6 - 176 x 125 mm
B7 - 125 x 88 mm
B8 - 88 x 62 mm
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C Formats/ Envelopes:
C format is used for envelopes, they are created so that A format papers can fit inside a C envelope without being folded more than twice.
The Dimensions:
C0 - 1297 x 917 mm
C1 - 917 x 648 mm
C2 - 648 x 458 mm
C3 - 458 x 324 mm
C4 - 324 x 229 mm
C5 - 229 x 162 mm
C6 - 162 x 114 mm
C7 - 114 x 81 mm
C8 - 81 x 57 mm
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Perfect Binding:
Perfect binding puts all the pages or together, roughens and flattens the edge, then a flexible adhesive glue attaches the paper cover to the spine. Paperback novels are one example of perfect binding. Telephone directories and booklets also use perfect binding as it can work for publications which are a few inches thick. It is relatively an average costing binding method and it is very popular with commercial print.
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Saddle Stitch:
Saddle stitch binding can be done with cotton/string or staples. The most common process is to simply staple down the centre of the booklet, this is very effective but cannot be done on very thick publications as it is not strong enough. Cotton saddle stitching can be done by person or by a machine. It is a very popular way to bind and it is probably the easiest.
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Wire Binding:
Wire or Wire-O binding is another very popular way to bind a booklet or file. It is done with a small machine which punches a series of wholes down one side of the paper and then wire is fed through the wholes, force is then added to the wire which bends it into an O shape which keeps the book together. It is a popular way to bind but it is very time consuming unless it is done by a machine.
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Japanese Binding:
Japanese binding involves 4 wholes and a long piece of cotton/string. Four wholes are made in the book and the cotton is hand sewn through the publication. This process is more popular with hand made bespoke books rather than large print runs in commercial print.
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Concertina Binding:
Concertina binding does not involve anything other than the paper itself. A series of folds/creases to create a fan-like effect which will create a small unbound booklet. This is the most simple of all binding as it does not require any specific technique or any other equipment to achieve the effect.
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