BOOK 1 - Designing for print
COLOUR
Basic terminology
Within
colour there are a lot of ways in which it can be described, using the
following terms can help you communicate colour.
- Describing
colour
As colour is
different wavelengths of light, professionals use different values of hue,
saturation and brightness to describe it. There are two main colour modes in
which most designers work in:
- CMYK
This colour
mode is made up of cyan, magenta, yellow and black. This colour system is
subtractive, because as the colours overlap each other they combine and create
a darker colour. As the C, M & Y overlap each other they create the RGB
colour system, when all three overlap they create black. This colour system is
used for print based media.
- RGB
This colour
mode is made up of Red, blue and green. This colour mode is addictive, because
when the colours overlap and combine they create a lighter colour. As each
individual colour overlaps each other they create the CMYK colours. When all
three colours combine they create white. This colour mode is used for on screen
design.
Brightness, hue and saturation
These terms
help a designer specify and communicate the colour information. Using these
terms the designer and client can meet the expectations of the client.
- Hue - hue
or colour is the unique characteristic of a colour that helps us visually
distinguish one colour from another. Hues or colours are formed by different
wavelengths of light.
- Saturation
- saturation or chroma refers to the purity of a colour. Saturation levels
describe a colours tendency to move towards or away from grey.
- brightness
- this is how light or dark a colour is. Changes of brightness can be achieved
by adding black or white to a colour.
COLOUR MANAGEMENT
Colour
management is the process that governs how colour is translated from one
machine to another in the printing process. Colour management is needed to
produce a consistent colour throughout the print process. Different machines
respond and produce colour different, so you need to make sure you use the same
colour throughout all print matter.
- Gamut
& Colour space
Gamut and
colour space are used by designers and printers to calculate the amount of
colour that can be produce within a colour mode's range.
- Gamut
In the print
industry the gamuts that are used are RGB & CMYK dependant on what the
design is for depends which gamut needs to be used. The human eye can see more
colours than what blithe RGB & CMYK can produce, which is a limitation, but
one that the designers have to work with. RGB has a bigger colour range as it
is used for on screen design, whereas CMYK is limited because of the inks used
to print.
- CMYK gamut
When
designing for print, you need to make sure that you are working in CMYK mode
and when working with colour, this needs to be within the CMYK colour range,
the best way to ensure this is by using the CMYK colour sliders to mix a colour
within the software. If you use the colour picker this will show all colours
available to use, but not necessarily ones that can be produced when printed,
if a colour you select isn't within the CMYK colour range then a exclamation
mark will appear next to the colour. The easiest way to get around this is to
click the exclamation mark and it will select the next closest colour that is
available in the CMYK colour range.
Another way
to solve this problem is to use the 'gamut warning' within photoshop, when this
is turned on the image you are working on will have grey areas over the
sections of colour which cannot be produced when printed, to correct this you
can use the 'hue/saturation' or 'levels' correction tools to bring these
colours back into the colour range. The grey area will reduce when the colours
are within the colour range.
- Colour
space
A colour
space provides a definition for the numerical value of the combination of
colours present in a given pixel, each value will represent a different colour.
Each different device uses a different colour space, so this value will always
be different dependent on the device you use.
Changing the
colour space will change the colour associated with that value, so you must
make sure you are aware of the colour space an image or design is using when
editing it.
PANTONE AND SPOT COLOUR
Designers
use a spot colour to make sure that a given colour in a design will print that
exact colour. The main reason would be if a certain colour has be consistent
across different formats and stock, or if a colour is outside of the colour
range and cannot be produced from CMYK.
- Spot
colours
A spot
colour is a ready mixed ink, that has no combinations of colours mixed
together, it is one single ink. When printed a spot colour prints as a solid
colour and is not transparent in any way.
As said
above designers will use a spot colour to print a certain colour in a design
exactly the same, if printing across different stocks or in mass. This will
make sure a consistent print quality is met for the design and it will look the
same on every print.
It could
also be used if the colour needed is outside of the colour range, or if a
specific colour has been specified by a client to be used.
Other
reasons may include:
If the
colour was overlapping another colour, so it would prevent the colours from
mixing. Or if the design needs a specific colour to be more vibrant or stand
out from the rest a spot colour would be used.
- Mixing
spot colours
As we have
already discussed, spot colours are ready mixed inks, you can either buy these
as mixed inks in pots or mix them using various base elements to a specific
recipe. You can also mix up spot colour using other ready mixed spot colours.
Some printers can mix this in house for you.
- Pantone
colour system
The Pantone
colour system is system which we use in England for spot colours. It is a
system which allocates a unique reference number to each colour combination.
Every Pantone library is exactly the same, which makes it easy for designers
and printers to work together.
When a
Pantone colour is used within a design, the colour combination and reference
number is stored within the document information, so when the printer receives
the document he can find this colour combination to use within the print. It is
a very simple but effective system which makes the printing process a lot
easier and more efficient.
All design
software will include the Pantone colour system within it, so any designer can
access the libraries where ever they are.
CREATIVE COLOUR TECHNIQUES
Colour makes
a design more dynamic and aesthetically pleasing, by elevating certain elements
and attracting attention to specific parts of the design. Creative colour
techniques can dramatically change the appearance of a design and also add to
it.
- Colour layers
The first
and easiest way to use colour creatively within a design is to use the blending
options, these are preset blending modes which can be used when layering images
on top of each other. The good thing about this is that the original image
below will keep its contrast and detail intact.
- Multi-tones
Multi-tones
are again layers of colour built up on top of an image, there are several
different types:
- monotone
// duotone // tritone // quadtone
- Monotone:
All multi-tone images start off being monotone and use a monotone image as the
base layer. A monotone image is one that works with one colour only, this can
be any colour and tends to be done with spot colours. If you are creating a
duotone etc then the base monotone image, normally is made with black.
- duotone: a
duotone image is one made up of two colours. The first colour would usually be
black and be the basis of the monotone base image.
- tritone:
this is an image that is made up of three colours. Within photoshop there are
presets set up that use tritones such as: sepia and other image overlays.
- quad tone:
an Mage made up from four colours.
Half tones
The printing
process that uses CMYK but produces them in different sized half-tone dots.
When viewed once printed the eye is fooled into seeing a continuous image, but
really it isn't.
If you are designing a booklet then the
outcome has to have pages in multiple of 4, as once sheet of paper will hold 4
pages.
The same rules as above applies to the use
of panels, which is another way to fold a printed sheet.
Add
in screen angles
Tints
and mixing colours:
Process and special colours can be used
along side tints and overprinting to introduce new colour effects within a
design.
Tints
A tint is a colour, which is created by
using either a spot colour, a CMYK or RGB process colour. Using these colours
you mix it with white to create a lighter version of the original colour. To do
this within digitally, you would select the colour and make it a global swatch,
when you then go to the colour slider it will only let you edit the swatch
colour as a tint.
The advantage of using a tint is if you are
limited to a certain number of colours within a design, using a tint will
introduce a new colour but only use the same colour ink when printed. It is a
good way to get around a limited colour design and print budget, but still
design a good piece of artwork.
Overprint
Overprint is where once ink overlaps
another and when printed they mix to create a different colour. To overprint
effectively, you need to know the order in which the process colours print, in
order to use overprint to the best of its ability. Overprinting can produce
creative effects within a design piece and works well when used with graphics
and images.
Add
in info from pre press overprint
Multi-ink
Tints of two colours or more process
colours can be combined to create a new colour combination, using the multi-ink
tool.
When creating a multi-ink you can select
different colours and tints to mix, changing the percentage of each colour in
the mix, will effect the outcome of the new colour; as more colours are
selected into the mix, the colour will become darker.
This is a useful tool to use, if you are
restricted to a two-colour design, as mixing them two colours in different
percentage will introduce new colours that you can use within the design.
A
Note about percentages within a colour mix:
As a CMYK ink can be applied with a value
ranging from 0 to 100 percent, a colour will therefore be expressed as a
percentage of each colour within the mix. The total number of these values
shouldn’t exceed 240 because any colour over this amount will result in a
‘muddy’ colour.
You can also have the opposite effect if
not enough colour is added to the mix and the colour becomes too light, and
when printed it won’t register properly; this is referred as a ‘drop off’.
Tints are produced using half-tone dots, so
a rule with mixing tints is that you must you at least 10% of an ink within a
colour mix, anything less than 10% may not be reproduced well in the printing
process
Tint
Charts
Tint charts show the different variations
of colours that can be obtained when you combine different colour together. Using
Cyan, Magenta and Yellow, you can create over 1,000 new tints and if you
introduce Black then even more can be created.
A tint chart is created so that designers
have a reasonable idea of what a colour combination will look like when
printed. But they must remember that it is not 100% accurate as there are
dependents such as – colour control, the press used and stock used that could
determine the outcome of the colour.
ARTWORK
Here we will talk about artwork in the
means of how to set up and use the document within a software program. This
will cover the basics of formats and registration to trapping and knockouts.
All these aspects of the artwork need to be correct in order to produce a
accurate print.
Document
set up
Setting the page right:
Once you have sent your work to print, it
is very unlikely that you will be able to make changes to the file or correct
any mistakes. Making sure the document is right and everything is set up
correct, it is necessary to spend more time on this.
-
Preparing colour for print:
Once a piece of design has
been completed, the designer will carry out a number of checks to make sure the
document is set up right, so that there is clear communication between the
designer, printer and client.
The designer must review
certain aspects of the document that may cause problems during the printing
process. Innovative use of the printing
processes can also help reduce the printing cost. Using the checklist below
will eliminate some of the problems, which could occur when printing:
1.
Delete all unused colours
2.
Ensure all that you want to
print in black is actually black, not registration
3.
Ensure that everything that
should be in registration is registration and not black.
4.
Ensure all spot colours are
accounted for, if the job is printing with special colours it is okay, if the
job is printing with CMYK, make everything CMYK
5.
Ensure all images are converted
to CMYK and not RGB; This includes logos, maps additional icons. In some
circumstances it may be better to leave them as RGB, so they convert themselves
to the right colour profile, but that will be specified.
6.
Ensure you are clear that your
colour-fall matches the printer’s expectations. If a four colour job is been
requested to print, then make sure the document specifies four colours to print
with,
7.
Ensure your imported swatches
are of the right value, if the job is being printed on uncoated stock, and then
make sure the spot colours are from the uncoated library.
Printed
pages and panels:
Printed pages are the actual number of pages
printed and not the number of sheets printed on.
E.g. a booklet that is made up of four
sheets with print on every side will have eight printed pages once folded.
The easy way to remember this is that one
sheet printed double sided is equal to two printed pages.
-
Formats
Standard paper sizes
provide a convenient and efficient means for the designer. It enables the
designer and printer to communicate well and know that the design will be
printed to the correct specifications.
-
Paper and envelope sizes:
Standardised paper sizes
provide a all round ease of selecting paper and which size to use, having the
different paper sizes which all together make it way for a designer to plan
what sizes they need to use for a design, also when printing you can print multiples
and set it up easy.
ISO – The ISO standard provides
a range of standard paper sizes, so that it can cater for all common printing
needs. The ISO range of paper is split down into 3 categories; A , B and C
sizes, each category is used for a different purpose:
-
A sizes – This series of paper
sizes is used for all print matter. It is used to print anything from posters
and technical drawings to magazines, office paper and postcards.
-
B sizes – This series of paper
sizes are used for printing books
-
C sizes – This series of paper
sizes are used for printing envelopes to fit A sizes. Also known as DL.
DL
The DL envelope sizes allow an A4 sheet
with two horizontal and/or parallel folds to fit inside. The envelope and any
DL sized compliment slips are the same width as an A4 sheet of paper.
SRA & RA
SRA paper sizes are used in commercial
printing companies because it is slightly larger than the A series and provides
room for grip, trim and bleed which is needed for an accurate print. These
paper series are untrimmed raw paper. RA stands for ‘raw format A’ and SRA
stands for ‘supplementary raw format A’. Once the sheets have been printed and
binded, it will be cut down to match the A format.
Book
and Poster Series:
- Book sizes
Books come in a wide
variety of sizes, to provide a range of different formats to suit different
types of content that will be used within books. A book format is determined by
the size of the original sheet of paper used to print on.
Folio editions are formed
from signatures once folded to make the separate booklets. Quarto editions are
made from signatures folded twice and Octavo made from signatures folded three
times.
Each edition and book size
is based on the standard ISO and RSA paper sizes, so they will have a relation
to one of the paper sizes within those series.
-
Poster sizes
Posters also work to a
standard size series to make the production of them much easier and simpler.
The A series poster system is based on the single sheet which is 762 x 508 mm
in the portrait orientation.
The rest of the series is
made up by using multiples of this:
-
4 sheet – 1524 x 1016 mm
-
12 sheet – 1524 x 3048 mm
-
48 sheet – 3048 x 6096 mm
-
96 sheet – 3048 x 12192 mm
Bleed,
registration and trim
When printing your work, the responsibility
of the accuracy and quality of it, is passed onto the printer, but there is
ways in which you the designer can reduce the margin of error within your
document.
The simplest way to do
this is by using bleed and slug within a document.
-
A bleed is an area outside of
your artwork, usually 3mm (can differ with different printers, but they will
specify) that you would extend all the elements in design near the edge of the
printed area to. A bleed is usually used if the artwork goes right up to the
edge of the page, extending the design past the edges and into the bleed means
when the design is trimmed down to the correct size no white/stock colour will
be left behind.
-
A slug is again an area outside
of the print area; this extends outside of the bleed and is used for any
document information. It will display the document name and time printed, you
can also add more details to be printed into this area during the printing
process:
-
Trim marks
-
Notes
-
Registration marks
-
Colour mode
Once the document has been
trimmed the all the information within the slug area will be cut away.
Registration
Registration is used to align two or more
printed images with each other on the same stock.
If you are doing a one colour print job
then registration is no problem as there will be nothing to align within the
printing plates. The issue is when you come to using two or more colours, in
the commercial printing process each colour within a design is printed on a
separate printing plate, so registering these plates on top of each other is
difficult. Mis-registration can cause a blurred image or show the different colours
used in the mix within the design. To make the registration more accurate you
can add registration marks to your document, this will print on every colour
layer and be a way in which the printer can align each layer together.
Trim
Once your artwork has been printed, the
printer will then take it to be trimmed. This process is where the waste stock
around the edge of the artwork is cut away to leave the final design and
format.
To trim the artwork down, you would add
trim marks to your document, which will be displayed in the bleed and slug
area.
Trapping
When printing a colour job especially one
that contains two or more colours, which overlap, the one thing you need to be
accurate is the colour registration. This is not always possible and is a
factor that you can never control. However there is a way in which you can help
eliminate this, which is by using ink trapping.
Trapping is the compensation for mis-registration between
printing units on a multicolor press. The process involves creating overlaps (spreads) or under laps
(chokes) of objects during the print production process.
Important:
The
‘lighter’ color within a design should always be spread into the darker. This reflects
the way the human eye perceives color: since the darker colors define the
shapes we see, distortion of the lighter color will result in less visible
distortion overall.
It
is important to know that the darker color always keeps its shape. The neutral
density of a color is used to determine its darkness.
Spread
and Choke
When
a mis-registration happens within a colour design, you will see a white gap or
the colour of the stock between the two colours, to stop this from happening
there are 3 ways in which trapping can be applied:
-
Spread - The lighter colour becomes bigger, because it spreads into
the darker colour (lighter colour in the foreground)
-
Choke – The darker colour becomes smaller, because the lighter
colour has expanded into that area. (lighter colour in the background)
-
Centered – Both spread and choke are applied – this is rarely used.
Knockout
and Overprint
Whilst
you can use trapping to register colour, there other techniques that don’t
involve trapping which can also reducing mis-registration; knockout and
overprint.
-
Knockout – The process in which you would remove an area within one
colour for the second colour that is printed on top to sit within.
-
Overprint – This process is
where the area of the two colours which overlap mix together and produces a new
colour.
Reverse out and Surprint
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