process and stock
DESCRIPTION
A handbook exploring different processes involved within print.TRANSCRIPT
Processes + Stock
Cont
ents
Con
tent
s
LithographyGravureScreen PrintFlexographyDigital PrintPad Printing + Six ColourFoil BlockingEmbossing/Debossing + Spot/ UV VarnishWeight + FinishLaid paper + Wove paper
ContentsC
onte
nts
1-23-45-67-8
9-1011-1213-1415-1617-1819-20
1
LithographyLith
ogra
phy
Lithographic (offset) printing utilizes the principle that water and grease do not mix. The image area of the plate is treated with a greasy medium. Then the plate is dampened with by rollers then inked. The ink adheres to the greasy image but not the dampened areas. The paper is moved into position over the plate and then the plate and paper are run through the press.
Lithographic has a planographic (flat). The whole surface has both ink and water with the addition of alcohol to aid dispersion.
Lithography first used smooth stone slabs to get a printing surface and this method is still used today for limited editions of fine art prints. The next development in printing came with metal plates which could be curved around metal cylinders to allow the use of rotary press. Finally the “offset” principle was developed.
Where Lithography is used, it is nearly always as Offset. Meaning the inked image on the metal plate is offset (printed) onto a rubber blanket wrapped around a rotating metal cylinder. The image is then transferred from that blanket onto the paper. The reason for the rubber plate is because it is less abrasive to the plate then paper.
2
LithographyLith
ogra
phy
Advantages 1. Good reproduction of detail and photographs2. Cheap printing surface3. Fast make-ready4. Rubber blanket enables the use of a wide range of papers
Disadvantages1. Colour variation due to problems with ink/water2. Dampening can cause paper stretch or warping
after binding3. Dense ink coverage dif-
ficult to achieve4. Fixed cut-off of web-offset restricts available
DAMPENINGROLLERS
INKING ROLLERS
PLATECYLINDER
OFFSETCYLINDER
IMPRESSIONCYLINDER
STOCK
3
GravureGrav
ure
“50,000impressions perhour”
Gravure is a modern day version of the intaglio process. This means that the printing image is recessed (indentation) into the cylinder with tiny hollows on a copper-plated plate cylinder. The indentation vary in depth so they will leave a required amount of ink on the various parts of the printed image. The non-image area is wiped free of ink with a doctor blade. Ink is then deposited on the paper from the indentations.
The ink is very thin and being spirit based dries through evaporation in a heated tunnel immediately after being printed.
Most Gravure is done with web-feed machines. Running speeds of up to 50,000 impressions per hour. Typical jobs generally include magazines or catalogs - very large runs. Printing is from a cylinder rather then a plate which allows speed. Gravure is also used for some kinds of packaging, printing on cellophane, decorative laminates and wallpaper.
4
GravureGrav
ure
FORM CYLINDER
BLADE
INK TRAY
PRINTING CYLINDERImpression roller
Advantages1. Simple printing method and press mechanism2. Can maintain consistent colour3. High speed4. Straightforward drying by evaporation5. Good results obtainable on cheaper paper
“50,000impressions perhour”
Disadvantages1. High cost of cylinders
2. Viable only for long runs 150,000+
3. Longer lead times than offset
4. High costs of proofs, if press proofs needed
5. High cost of corrections for reprints, as cylinder
5
Screen ScreenPrint
What is a line? Oldboy printsOUGD404
6
A synthetic fibre which used to be silk hence the name ‘silk screen’ is stretched across a wooded or metal frame.
The fibre is covered with a UV sensitive paint/ink which is left to dried in a dark room or somewhere out of the way of UV light. A stencil/artwork can then be placed onto the screen on top on the UV sensitive fibre. The screen along with the artwork placed in a UV light box and ‘exposed’. Exposing the frame allows the UV sensitive ink to
ScreenScreenPrint
Printbecome delicate where is has been exposed to UV light. When rinsed with a hose or jet wash crumbles off the frame leaving the UV paint which was hidden by the artwork/stencil.
Ink is then placed onto the frame and pushed through the fibre onto paper using a squeegee. The paper is laid onto a flat vacuum table. The vacuum holds the paper still. The frame can be placed directly onto the paper or it can be fixed into a set position using a holding which is fitted to the ‘bed’
Advantages
1. Can print a heavy fi
lm of
ink2. E
conomical for short runs
(Even below
100 copies)3. C
an print on virtually any m
aterials
Disadvantages
1. Diffi
cult to achieve fine
detail2. V
ery low screen halftone
3. Low
output qualities4. D
rying requirements
FlexographyFlex
ogra
phy
7
“Engraved etchings that hold the ink”
IMPRESSIONCYLINDER
PLATECYLINDER
ANILOXROLLER
PRINTINGCYLINDER
FOUNTAINROLLER
INK
DOCTORBLADE
STOCK
on cellophane,
plastics and
metallic
foils. It
is generally
used to
produce som
e of
the cheaper
magazines
and
newspapers.
A
good proportion
of new
spapers are
printed using
this m
ethod as
the inks
doesn’t suff
er the
balance of
water
and ink. T
he ink
dries instantly
and doesn’t
come
off on
the hands
of the newspaper reader.
This m
ethod of printing is ideal for short runs of prints, colour and black and w
hite work. U
nlike m
ost other
printing techniques
it doesn’t
require film
or a plate to be m
ade which m
akes the start up process cheaper. A
lthough the
start up
cost is cheaper the cost per print is higher then off
set litho.
FlexographyFlex
ogra
phy
8
IMPRESSIONCYLINDER
PLATECYLINDER
ANILOXROLLER
PRINTINGCYLINDER
FOUNTAINROLLER
INK
DOCTORBLADE
STOCK
Flexography is
the process
that is
a derivative of letterpress, using
flexible photo
polymer plates and thin,
fluid inks
(often now
w
ater-based rather than spirit-based) that dry by evaporation
(sometim
es assisted
by heat)
The
image is raised as in the
conventional form
of
letterpress printing.
Most
flexographic printing presses are w
eb-fed because of the nature of
the products
they are
usually em
ployed to
print. Ink
is applied
to a
plate by
a m
etal roller;
"anilox" roller,
this roller has engraved etchings
that hold
the ink and transfer it onto the
flexible plate
for printing. M
any machines
are multi colour presses,
for four-colour work.
Mainly
used for
packaging printing
9
Digital PrintDigi
tal P
rint
This m
ethod of printing is ideal for short runs of prints, colour and black and
white
work.
Unlike
most
other printing techniques it doesn't require film
or a plate to be made w
hich makes
the start
up process
cheaper. A
lthough the
start up cost is cheaper the
cost per
print is
higher then offset litho.
Digital printing uses files such as PSD
, JPE
G etc transferring the im
age digitally to the printer, this technique of print-ing
has allow
ed both
ultra-short run
reprinting and
"print on
demand"-
Exam
ple w
ould be
offset litho
needs a minim
um run of
around 500 in order to be econom
ical.
With
digital printing
the publishers
can produce order of one print which
can be printed quickly. Digital print
quality is general inferior to offet-litho especially w
hen the job has large areas of flat tints or solid colours. H
owever
this is rapidly changing as technology is constantly m
oving forward fast and the
price of digital print is reducing.
10
Digital PrintDigi
tal P
rint
Advantages
1. Econom
ical for short runs (500 or less)2. E
nables personalization of data3.N
o film or plate cost
4. Shorter lead time
5. Large formats possible w
ith ink-jet printing
Disadvantages
1. Quality of som
e digital printers is inferior to offset.2. C
onsumerables (toner/paper)
11
Pad PrintingPa
d Pr
intin
g
SOLVENTSEVAPORATEFROM THE INK
PAD PICKS UPTACKY SURFACEOF INK
PAD DEPOSITSTACKY INK ONTOSUBSTRATE
SOLVENTSEVAPORATEFROM THE INK AS THE PADMOVES TO THEPRINTPOSITION
Pad printing is a printing process that can transfer a 2-D image onto a 3-D object. This is accomplished using an indirect offset (gravure) printing process that involves an image being transferred from the solid plate via a silicone pad onto a substrate (stock/material).
Pad printing is used for printing on otherwise impossible products in many industries including medical, automotive, promotional, apparel, and electronic objects, as well as appliances, sports equipment and toys. It can also be used to deposit functional materials such as conductive inks, adhesives, dyes and lubricants.
12
Hexachrome is an ultra-high fidelity six-color process printing system developed by Pantone, Inc.
Hexachrome adds orange and green to the traditional CMYK inks for a larger and more vibrant gamut, or color range. However, such alternate colour systems still rely on color separation, half toning and lithography to produce printed images. Accurately reproducing a wide range of both vibrant and subtle colors that can be defined and displayed on computer monitors which previously could not be duplicated in print.
Six ColourSi
x Co
lour
13
Foil BlockingFoil
Bloc
king
Foil blocking, oil stamping, hot
stamping, foil im-printing & leaf imprinting.
Foil blocking also called foil stamping, hot stamping, foil imprinting and leaf imprinting - uses a heated die strike to apply a colored, clear, metallic, matte, pearlescent, holographic, or otherwise tinted foil to another surface. Foils can be opaque or semitransparent. The process can be combined with embossing for a dimensional effect; applied on top of flat printed graphics for a bit of shine or extra emphasis; or used alone to create its own effect.
The stamping process is a mechanical one- a heated die imposes the foil onto the printing surface. Registration can be a bit off from hit to hit. Type sizes should stay above 8 point and lines should be no thinner than 2 points. Foils tend to fill in tight areas, such as tightly kerned type or lines that are closely spaced; generally a good idea to use in more open areas.
Smooth, coated stocks work best for foil stamping. Uncoated or textured surfaces present an irregular surface that may disrupt and break up the foil. Large areas of stamping can bubble on highly coated stock if the chemistry between the two layers is not carefully considered. Also foil blocking on top of coatings or inks with high wax levels will also cause the foil to adhere improperly. Aqueous and other wax-free coatings are the best for using underneath foils; ask an experienced foil stamp supplier for guidance on getting the most effective results.
Some foils can scratch easily, especially in large flat areas, so make sure the clients are aware the stamped surface could become marred with use.
Foil blocking, oil stamping, hot
stamping, foil im-printing & leaf imprinting.
Foil
Bloc
king
Foil Blocking
14
15
Embossing/DebossingEmbo
ssin
g/De
boss
ing
Em
bossing/debossing and
de-bossing takes
printing into a third dim
ension. Paper is pressed betw
een two m
olds called
a die,
that sculpt
its fibers by as m
uch as 1/8 of an inch. Im
ages higher than the rest of the paper are em
bossed; im
ages lower are de-bossed.
Both
are produced
under heat to assure fine detail.
Heat also m
akes the images
smooth and shiny. E
mbossed
impressions
made
without
having to
register over
a previously printed im
age are said
to be
blind em
bossed. B
lind im
pressions cost
less then
impressions
over ink
because press operators don't have to register dies precisely.
Dies
are m
ade from
either
magnesium
or brass.
You should
not try
to use
lines that
are so
fine that
paper doesn’t press into them.
Deep dies need beveled edges
to avoid
cutting the
paper. A
nd beveled edges optically reduce the size of the im
ages, so
prepare the
original artw
ork slightly over sized.
16
Spot/UV VarhishSp
ot/U
V Va
rnis
h
Spot
/UV
var
nish
is
a cl
ear
liqui
d th
at
is ap
plie
d lik
e in
k an
d cu
red
inst
antly
with
ul
trav
iole
t lig
ht. I
t can
pro
vide
ei
ther
a g
loss
or
mat
t co
atin
g.
Incr
easin
gly,
UV
va
rnish
is
used
as
a po
t co
veri
ng t
o hi
ghlig
ht a
par
ticul
ar i
mag
e be
caus
e it
prov
ides
m
ore
shin
e th
an v
arni
sh.
The
va
rnish
is
appl
ied
to
high
light
disc
rete
are
as o
f a
prin
ted
desig
n, b
oth
visu
ally
an
d by
im
part
ing
a di
ffere
nt
text
ure.
The
eff
ect
of
spot
U
V c
an b
e m
axim
ised
whe
n ap
plie
d ov
er M
att-
lam
inta
ted
prin
ting.
WeightWei
ght
Weight (gsm)
Paper is mostly defined by its weight using gsm (grams per square meter) or g/m2; This is called grammage.
Photocopier papers are usually around 80 gsm; letterheads and pamphlets, around 110 gsm and posters, around 170 gsm; lightweight covers.
17
18
FinishFini
sh
Commercial printers commonly distinguish between coated and uncoated paper.
Coated paper can be further devided into additional categories depending on the amount of coating it has: lightly coated, medium coated, highly coated or art paper. Coated paper has a smoother surface which gives it a higher printing quality. Examples include brochures and high culture magazine covers. Examples of uncoated papers include stationary, photocopying and pages of paper back books.
“Uncoated paper is not necessarily cheaper than coated.”The surface of the paper can be calendered to obtain a higher sheen. A coated paper can be matte or glossy. Uncoated paper can be calendered.
A glossy paper gives a good reproduction of image and colour, while text readability is poor because of distracting reflections. Matte and/or uncoated paper is generally more suitible for readability, the texture is smooth but non-reflective, which means that the paper is treated with this coating will produce prints with a combination of high image quality and readability.
finish: gloss/silk/matt, coated or uncoated
19
Laid PaperLaid
Pap
er
This page is printed on Laid paper!
There are basically two types of paper - wove and laid. A wove paper is produced on a closely woven mold or screen and shows no impression from the mesh of the screen.
20
Wove PaperWov
e Pa
per
This page is printed on Wove paper!
A laid paper is produced on a coarser screen or mold supported by wires which unlike wove paper is textured.