Printing - Worthing High School

Learning objectives
All- will be able to respond to the questions in some detail and
have some understanding of the answer (D)
Most -will be able to back up responses with examples (C)
Some – will have a detailed answer and explain answers in
depth (A/B)
• Literacy- Read the question carefully
• Numeracy- Marking your own work/ Using problem solving
skills
• SMSC- Reflect on knowledge and use thinking skills
STARTER
• Watch the video:
• Write down all the printing and finishing
methods you see or hear on the clip
• http://www.bbc.co.uk/schools/gcsebitesize/d
esign/graphics/
Learning objectives
Learning objectives
To learn about:
the different printing methods available
four colour process printing
the printing effects that can be applied to printed products
quality checks that are performed on printed products.
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© Boardworks Ltd 2005
Printing
methods
Graphic products can be printed in a variety of different ways. The designer has to select
the printing process that suits their product best.
This will depend on the length of the print run, the quality required, the paper or card
needed, and the project’s budget.
The designer will choose from the following printing methods:
letterpress
lithography
flexography
gravure
screen printing.
Printing methods
Letterpress
Letterpress is one of the oldest forms of industrial printing. Letterpress is known as a relief
printing method, because the printing plate is not flat.
A printing plate is prepared with the image to be printed raised above the surface of the
plate, standing proud
of the non-printing area.
The raised surface is coated with ink and is then pressed
onto the paper.
It is an expensive process, as the plate has to be
specially made and high quality paper is needed. It is
used for high quality books and stationary.
Lithography
Printing methods
Lithography is the most commonly used
process in the printing industry.
The image is transferred onto the completely
flat printing plate photographically, using UV
light.
The plate is washed in a chemical
that makes the image area attractive to the oil-based ink.
The non-image area is dampened with water to repel the ink.
Lithography is used for medium to large print runs because the set-up costs are high.
Printing methods
Flexography
Flexography is very similar to letterpress as it uses
a relief plate. As the name suggests, the relief
plate is made from a flexible material, like rubber.
It is used to print on unconventional materials,
like polythene for packaging. Flexography is ideal
for these surfaces, because the ink is mixed with a
solvent that evaporates, causing the ink to dry
quickly.
Flexography is used on carrier bags and some wallpapers.
Gravure
Printing methods
Gravure is used to produce high quality photographic images. It is very good for
reproducing fine detail. However, gravure is a very costly process due to the skill needed to
manufacture the printing plate.
It is the opposite to letterpress – the printing
areas are in fact lower then the non-printing
areas. The image is engraved onto a copper
plate, creating cells that are filled with a spirit
based ink. The paper is pressed against these
cells to produce the image. The ink evaporates
quickly once printed.
Screen printing
Printing methods
Screen printing is completely different to any other printing method. It works by forcing
ink through a stencil. The stencil shape reflects the image to be printed. The stencil can
be made of paper or card and is supported by a fine mesh.
The ink is spread over the mesh using a spreader, and
then forced through the mesh onto the surface to be
printed. Stencils can be made fairly simply, but to create
more complex images, a photographic stencil is required.
These have to be made by
a professional or using a computer.
Printing methods
Die cutting and folding
Guillotines can be used to cut
straight edges on batches of card
and paper. Die cutting is used
when the shape is irregular.
A blade similar to that of a cookie cutter is made, and the design is stamped out. This can
be done by hand or using a hydraulic press.
Folds are created in a similar way, except that the blade does not cut all the way through
– it creates a crease instead.
Printing effects
You can add interest and impact to a graphic product by adding a printing effect. There are
lots of printing techniques to choose from, but they can restrict your choice of materials
and add to the final cost.
The designer can choose from the following printing effects:
Spirit Varnishing
UV Varnishing
Embossing
Laminating
Varnishing
Printing effects
Applying varnish to a product has two main
functions:
to protect the product
to make the product look better.
Varnishing is done after printing but before any cutting, folding or trimming.
There are several different types of varnishing. Oil-based and water-based varnishes
are sometimes used, but the most important types of varnishing are spirit
varnishing and ultraviolet varnishing.
Printing
effects
Spirit varnishing
Spirit varnishing involves applying a spirit-based coating to the product to
produce a high-shine finish.
It is relatively cheap, but the ink must be completely dry before the varnish is
added, making the manufacturing time longer.
UV varnishing
Ultraviolet varnishing involves applying a thin coating of liquid plastic, and then
hardening it using UV radiation.
It gives a tougher, glossier finish than spirit-based varnishing, but is more
expensive. It cannot be added until the printing ink is completely dry.
Printing effects
Laminating
(or encapsulating) produces a
tough,
high gloss finish.
The image is sealed between two
layers of plastic. It is twice as
expensive as varnishing, but the
end result is of a lot better quality.
HOT
LAMINATE
COLD
LAMINATE
Lamination is used for products like menus that need to be
easily wiped clean.
Printing
effects
Embossing is when a portion of the surface is raised above the surrounding area.
It is used for two reasons:
visual impact
add texture
The required shape is
pressed into the work
using a steel die.
Embossing can give an expensive, high quality
feel.
Printing effects
Process colours
To reproduce a full colour image or document, commercial printing companies use what
is called ‘four colour process printing’.
The four colours are called the ‘process colours’. They are overlaid to produce the full
range of colours. The process colours are:
Cyan
Magenta
Yellow
Black
These colours are known
as CMYK. Black is
represented by the letter
K so it is not confused
with blue.
The image is separated into the four process colours, and a separate printing plate is
produced for each. This is known as ‘colour separation’.
Process colours
This image shows the colour separation for the picture in the top left hand corner.
Quality checks
Quality is essential in all products – printed products are no exception. When a document
or item is printed, a series of marks are created that allow manufacturers to check that the
printing has been done correctly:
Registration marks
These marks allow printers to check
alignment. If the colour plates are aligned
properly, the mark will appear black.
Colour blocks
Allow you to check the colour
for correct tone and equal
density.
Plenary
Key points
There are many different printing methods available, including
letterpress, lithography, flexography, gravure and screen
printing.
Key points
Die cutters and creasing bars are used to cut out shapes and
create folds accurately.
You can add interest and texture to graphic products by
varnishing, laminating or embossing them.
Commercial printers usually use four colour process printing,
which involves colour separation.
Registration marks and colour blocks are used to check print
quality.
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© Boardworks Ltd 2005
QUESTIONS TO COMPLETE
USE
www.technology.com
To answer the questions
QUESTIONS TO COMPLETE
QUESTIONS:
1. What is embossing?
2. Describe how embossing could be applied to the package, designed for
commemorative stamps.
3. How would embossing a stamp be of benefit to the visually impaired?
4. Draw a diagram to represent the application of varnish to card.
QUESTIONS TO COMPLETE
5. Explain why varnishing is applied to card and paper.
6. Draw a simple diagram of a laminating machine and explain how it works.
7. When is it a good idea to laminate card - give three examples.
8. With the aid of diagrams, describe how a card embossed shape is created
9. Using notes and diagrams show how a die-cutter works
10. Explain why sometimes there is a need to use special printing effects
PLENARY
MIND MAP FOR PRINTING
Produce a mind map of your learning. This could be
done using concept branches, key words, 3 things
they have learnt etc.