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1. Created By – Rizwan Rajik Qureshi

2. Project Report
On
Submitted by
Mrs. Jyotsna Chopkar
(Bachelor of Textile Science, III Year)
Under the Guidance of
Mrs. Snehal Rohadkar
BACHELOR OF TEXTILE SCIENCE
MAHALAXMI JAGDAMBA COLLAGE OF LIBRARY & INFORMATION SCEINCE
RASHTRASANT TUKDOJI MAHARAJ NAGPUR UNVIVERSITY,
NAGPUR.2018-2019
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3. Is a record of dissertation work
Carried out by
Mrs. Jyotsna Chopkar
It is certified that all the corrections/suggestions
indicated for internal assignment have been
incorporated in the report. The project report has
been approved as it satisfies the academic
requirement in respect of project work
prescribed for the said degree
MAHALAXMI JAGDAMBA COLLAGE OF LIBRARY & INFORMATION SCEINCE
RASHTRASANT TUKDOJI MAHARAJ NAGPUR UNVIVERSITY,
NAGPUR.2018-2019
Mrs. Snehal Rohadkar
Guide
Mrs. Janvi Nandanvar
Principal
Mrs. Meghna Polkat
Head of
Department
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4. Acknowledgement
“Many individuals with whose cooperation and motivation I could complete this
research work should be thanked. Though not all of them directly helped me, they
stood by me in very trying times with numerous words of encouragement and much
needed moral support.
First and foremost, I would like to thank my project guide prof. Snehal
Rohadkar. Whose valuable guidance, suggestions and constructive criticism has
helped me bring this project to its present form.
I am grateful to prof. Meghna Polkat H.O.D of textile, M.J.College Nagpur for
their help, encouragement and other facilities extended while carrying out the
project.
I am thankful to prof. Dilip Varma, In-charge MGIRI lab, Wardha, prof. cinnur,
MGIRI Wardha, who had helped and assisted me in completing my project.
Little room to write and so many people are there, I take this opportunity to
thank all faculty members and non-teaching staff members of M.J.College,
particularly from printing, textile physics departments for their kind cooperation
during the project work.
The support I received from all my family members and friends was valuable,
without their support it would not have been possible to come out with this project
work. I am thankful to them all.
Mrs. Jyotsna Chopkar
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5. CONTENTS
 INTRODUCTION OF PRINTING
 INTRODUCTION OF SCREEN PRINTING
 HISTORY OF SCREEN PRINTING
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6. 1
HAND SCREEN
PRINTING
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7. 2
 INTRODUCTION OF PRINTING
Textile printing is the process of applying colour to fabic is definite
patterns or designs. In properly printed fabrics the colour is bonded with the fiber, so as
to resist washing and friction. In printing one or more colours are applied to it in certain
parts only, and in sharply defined patter.
In short, printing applying coloured patterns and design to decorate a
finished fabric is called ’printing’.
 INTRODUCTION OF SCREEN PRINTING
We have so far, studied the meaning of the original surface, and the
different printing system thereof. Now we shall study the procedures these printing jobs
under go, before the actual printing.
In the letter press, movable types are used. In this system, the jobs
undergo a unigue out –dated procedure. The matter is composed and proof is taken on
a manual instrument meant for it. This proof is then, sent to the customer for proof-
reading, after the proof is read, corrections, are made, and then the printing is done.
This procedure does not give any choice to the customer. This is the
reason, this procedure has become outdated in today’s advertisement oriented world.
What then is really required is the prior choice of type styles, their sizes, their alignment
illustrations, photographs, the different aesthetic way to make the product more and
more attractive, and the choice that aim at cost effectiveness.
Therefore, to facilitate the need of better choice, to increase the
quality of reproduction, to fulfill the urge of effective advertisement, to eradicate the
possibility of repetitive errors, to provide an easy storage and easier retrieval there after,
and also, to make the printers work more systematic every job that comes under
’printing’ in the modern times has to pass the following.
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8. 3
Visualization/ sample (in cases of preced)
a) a block or flexo-plate for letter press system
b) a plate for off-set or gravure system
c) A screen for screen printing
Every work has to pass through these phases, and final printing takes
place only there after. The first three steps are common, irrespective of what printing
system it is.
1. VISUALISTION
Now let us imagine, that we have decided to construct a building. Can we start
the construction as soon as we decide? No, certainly not. We have to go to an architect
first, who will provide us with a model of our choice. This model, is the sample of how
the building should look like, after its completion. This model will give us better
information about location of rooms, staircase , door , windows , the sizes there of :as
also the color scheme best suitable for the building etc. this will facilities choice and
architect will provide us with the plan for the construction of building. The actual work
with start only thereafter.
Likewise in printing industry a printer’s role is that of a builders. He goes
to a commercial artist who conceives an idea best suited for a given job. He then
presents the idea, so conceived, in the form of a sketch or drawing.
 HISTORY OF SCREEN PRINTING
Screen printing first appeared in a recognizable form in china during the song Dynasty
(960-1279 AD). It was then adapted by other Asian countries like Japan, and was
furthered by creating newer methods.
Screen printing was largely introduced to Western Europe from Asia sometime
in the late 18th century, but did not gain large acceptance or use in Europe until silk
mesh was more available for trade from the east and a profitable outlet for the medium
discovered.
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9. 4
Early in the 1910s, several printers experimenting with photo-reactive chemicals
used the well-known actinic light activated cross linking or hardening traits of potassium,
sodium or ammonium chromate and dichromate. Chemicals eithglues and gelatin
compounds, Roy beck, Charles peter and Edward Owens studies and experiments with
chromic acid salt sensitized emulsion for photo-reactive stencils. This trio of developers
would prove to revolutionize the commercial screen printing industry by industry by
introducing photo-imaged stencils to the industry, through the acceptance of this
method would take many years. Commercial screen printing now uses sensitizers far
safer and less toxic than bichromates. Currently there are large selections of
presensitizes and ‘user mixed’ sensitized emulsion chemical for creating photo-reactive
stencils.
A group of artist who later formed the national serigraphic society including
WPA artist Anthony velonis coined the word serigraphy in the 1930s to differential the
artistic application of screen printing from the industrial use to the process. ’serigraphy’
is a compound word formed from Latin ‘serium’ and Greek ‘graphein’.
The printers national environmental assistance center says ‘screen printing’ is
arguably the most versatile of all printing process. Since rudimentary screen-printing
materials are so adorable and readily available, it has Benn used frequently in
underground setting and subcultures, and the nonprofessional look of such DIY culture
screen-prints have become a significant cultural aesthetic seen on movie poster , record
album covers , flyers, shirts , commercial fonts in advertising , in artwork and elsewhere
1960s to presents.
Credits is generally given to the artist Andy Warhol for popularizing screen
printing as an artistic technique , identified as serigraphy, in the united states. Warhol
was supported in this production by master screen printer Michel caza , a founding
member of fespa , and is particularly identified with his 1962 depiction of actress Marilyn
Monroe, known as the Marilyn diptych , screen printed in garish colours.
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Sisters Mary corita kent , gained international fame for her vibrant serographs
during the 1960s and 1970s. Her works were rain bow colored, contained words that
were both political and fostered peace and love and caring.
American extrepreneur, artisr and inventor michael vasilantane started to use
,develop, and sell atotable multicolour garment screen printing machne in 1960s ,
vasilantone later filled for patent on his invention in 1967 granted number 3,427,964 on
feb 18 , 1969. The original machine was manufactured to print logos and team
information on bowling garments but soon directed to the new fad of printing on T-
shirts. The vasilantone patent was licensed by multiple manufacturing , the resulting
production and boom in printed T shirts made this garment screen printing machine
popular.creen printing on garment currently accounts for over half of the screen printing
activity in the united states.
Graphic screenprinting is widely used today a create mass or large batch
produced graphics , such as posters or display stands. Full colour prints can be created
by printing in cryan, margenta , yellow and black.
Screen printing lends itself well to printing in canvas. Andy warhol , arthur okanurd
, robert Rauschenberg , roy lichtenstein , Harry have used screen printing as an
expression of creativity and artistic vision.
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11. 6
STYLE &
METHOD
OF
PRINTING
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12. 7
1. Direct
2. Vat
3. Discharge
4. Pigment
5. Azoic
6. Resist
7. Acrylic
8. Nylon
9. Soluble
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1. Block printing
The blocks are usually made of wood and the design is hand
carved, so that it stands out in relief against the back ground surface. The print paste is
applied to the design surface in the block and the block then pressed against the fabric.
The process is repeated with different designs and colours unit the pattern is complete.
2. Screen printing
This type of printing has increased enormously in its use in recent
years because of its versatility and the development of rotary screen printing machines
which are capable of very high rates of production. An additional significant advantages
is that heavy depths of shade can be produced by screen printing, a feature which has
always been a limitation of roller printing because of the restriction to the amount of print
paste which can be held in the shallow depth of the engraving on the print roller.
3. Roller printing
Roller printing has traditionally been preferred for long production
runs because of the very high speeds possible. It is also a versatile technique since up
to a dozen different colours can be printed simultaneously. The basic roller printing
equipment, consist of a number of copper faced roller in which the design is etched.
There is a separate printing roller for each colour being printed. Each of the rollers
rotates over the fabric under pressure against on iron pressure roller.
4. Batik printing
Batik involves decorating cloth by covering a part of it with a
coat of wax. The waxed areas keep their original color and when the wax is removed
the contrast between the dyed and undyed area gives the pattern. One of the significant
features of this art is that it is very simple and can be done by anyone.
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5. ink-jet printing
There has been considerable interest in the technology
surrounding non-impact printing, mainly for the graphic market, but the potential benefits
of reductions in the time scale from original design to final production has led to much
activity in developing this technology for textile and carpet printing process.
6. Carpet printing
The printing of carpets only really achieved importance
after the introduction of tufted carpets in the late 1950s. Until then the market was
dominated by the woven wilton carpets and ax minster designs were well established,
but by the 1980s tufted carpet production accounted for some 80% of UK production.
7. Direct printing
A process where the colors for the desired designs are
applied directly to the white or dyed cloth as distinguished from discharge printing and
resist printing.
8. Discharge printing
In “white” discharge printing the fabric is piece dyed, the
printing with a paste containing a chemical that reduces the dye and hence removes the
color where the white designs are desired. In “coloured” discharge printing, a color is
added to the discharge paste in order to replace the discharged color with another
shade.
9. Duplex printing
A method of printing a pattern on the face and back of a fabric with equal clarity.
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15. 10
SCREEN
PRINTING
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Screen printing is a printing technique whereby a mesh is used
to transfer ink onto a substrate, except in areas made impermeable to the ink by a
blocking stencil. A blade or squeegee is moved across the screen to fill the open mesh
apertures with ink, and a reverse stroke then causes the screen to touch the substrate
momentarily along a line of contact. This causes the ink to wet the substrate and be
pulled out of the mesh apertures as the screen springs back after the blade has passed.
Screen printing is also a stencil method of print making in which
a design is imposed on a screen of polyester or other fine mesh, with blank areas
coated with an impermeable substance. Ink is forced into the mesh openings by the fill
blade or squeegee and by wetting the substrate, transferred onto the printing surface
during the squeegee stroke. As the screen rebounds away from the substrate the ink
remains on the substrate. It is also known as silk-screen, screen, serigraphy, and
serigraph printing. One color is printed at a time, so several screen can be used to
produce a multicolored image or design.
There are various terms used for what is essentially the
same technique. Traditionally the process was called screen printing or silkscreen
printing because silk was used in the process prior to
the invention of polyester mesh. Currently, synthetic
threads are commonly used in the screen printing
process. The most popular mesh in general use is
made of polyester. There are special-use mesh
materials of nylon and stainless steel available to the
screen printer. There are also different types of mesh size which will determine the
outcome and look of the finished design on the material.
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A screen is made of a piece of mesh stretched
over a frame. The mesh could be made of a synthetic polymer, such as nylon, and a
finer and smaller aperture for the mesh would be utilized for a design that requires a
higher and more delicate degree of detail. For the mesh to be effective, it must be under
tension. The frame which holds the mesh could be made of diverse materials, such as
wood or aluminum, depending on the sophistication of the machine or the artisan
procedure. The tension of the mesh may be checked by using a tensiometer; a common
unit for the measurement of the tension of the mesh is Newton per centimeter (N/cm).
A stencil is formed by blocking off parts of the screen in the
negative images of the design to be printed; that is, the open spaces are where the ink
will appear on the substrate.
Before printing occurs, the frame and screen must undergo
the pre-press process, in which an emulsion is ‘scooped’ across the mesh and the
‘exposure unit’ burns away the unnecessary emulsion leaving behind a clean area in the
mesh with the identical shape as the desired image. The surface to be printed
(commonly referred to as a pallet) is coated with a wide ‘pallet tape’. This serves to
protect the ‘pallet’ from any unwanted ink leaking through the screen and potentially
staining the ‘pallet’ or transferring unwanted ink onto the next substrate. Next, the
screen and frame are lined with a tape. The type of tape used in for this purpose often
depends upon the ink that is to be printed onto the substrate. These aggressive tapes
are generally used for UV and water –based inks due to the inks’ lower viscosities. The
last process in the ‘pre-press’ is blocking out any unwanted ‘pin-holes’ in the emulsion.
If these holes are left in the emulsion, the ink will continue through and leave unwanted
marks. To block out these holes, materials such as tapes, speciality emulsions and
‘block-out pens’ may be used effectively.
The screen is placed atop a substrate. Ink is placed on top
of the screen, and a flood bar is used to push the ink through the holes in the mesh. The
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18. 13
operator begins with the fill bar at the rear of the screen and behind a reservoir of ink.
The operator lifts the screen to prevent contact with the substrate and then using a
slight amount of downward force pulls the fill bar to the front of the screen. This
effectively fills the mesh opening with ink and moves the ink reservoir to the front of the
screen. The operator then uses a squeegee (rubber blade) to move the mesh down to
the substrate and pushes the squeegee to rear of the screen. The ink that is in the
mesh opening is pumped or squeezed by capillary action to the substrate in a controlled
and prescribed amount, i.e. the wet ink deposit is proportional to the thickness of the
mesh and or stencil. As the squeegee moves toward the rear of the screen the tension
of the mesh pulls the mesh up away from the substrate (called snap off) leaving the ink
upon the substrate surface.
There are three common types of screen printing presses.
The ‘flat-bed’, ‘cylinder’, ‘rotary’.
Textile items printed with multicolored designs often use a
wet on wet technique, or colours dried while on the press, while graphic items are
allowed to dry between colours that are then printed with another screen and often in a
different colour after the product is realigned on the press.
Most screens are ready for re-coating at this stage, but
sometimes screens will have to undergo a further step in the reclaiming process called
dehazing. This additional step removes haze or “ghost images” left behind in the screen
once the emulsion has been removed. Ghost images tend to faintly outline the open
area of previous stencils, hence the name. They are the result of ink residue trapped in
the mesh, often in the knuckles the mesh (the point where threads cross).
While the public thinks of garment in conjunction with screen
printing, the technique is used on tens of thousands of items, including decals, clock and
watch faces, balloons, and many other products. The technique has even been adapted
for more advance uses, such as laying down conductors and resistors in multi-layer
circuits using thin ceramic layers as the substrate.
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Screen printing, also called serigraphy or silk
screening, is a technique of applying ink onto material (like paper, fabric, or canvas)
using a woven mesh and a stencil. The stencil is attached to the mesh or is created
on the mesh with photo- reactive chemical emulsions, and the ink is presses through
the mesh onto the material with a squeegee or a rubber blade. The stencil allows the
ink to pass through only where the artwork is located, leaving the design on the
material.
Because this process is relatively simple and the materials needed are fairly
inexpensive and easy to obtain, screen printing is a popular craft for hobbyists and
individual artists, as well as for commercial production. Those who are interested in
successful screen printing can benefit from a brief history of screen printing and from
an explanation of the eight steps for creating a screen print using photosensitive
emulsions, including several tips for doing each step successfully. They can also
search for and purchase screen printing materials and equipment at brick and mortar
craft stores.
The process of screen printing using mesh stencils made with
photosensitive chemical emulsions are explained below, with helpful tips for each
step to enable any artist (whether novice or expert) to achieve success in screen
printing.
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20. 15
A. Choose or create the artwork to be
screen printed
The best way to prepare artwork to be screen printed is
to have it copied onto a transparency. Most copy shops do this for a very small fee.
Original artwork can be painted directly onto a transparency or onto any piece of sturdy,
clear plastic. Beginners should create simple designs with fairly clear, thick lines since
screen printing delicate, fine – lined artwork can be tricky.
The objective is to create what artists call a “film positive” of
the artwork, which is 100 % black on a clear background. Whether it is printed or hand-
drawn, the artwork blocks the emulsion on the screen and the emulsion is washed off
the design, allowing the ink to pass through the screen and transfer the design onto the
T- shirt or other object that is imprinted.
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B. Gather the materials needed for
screen printing
Once the artwork to be screen printed has been selected and prepared, it is time
to gather the rest of the necessary materials and equipment. Object to be printed.
The screen printing can be done on paper, on canvas, or on just about anything
made from fabric, like a T- shirt, a tablecloth and napkins, a scarf, or simply a piece of
fabric that is framed and hung as art. The object should be clean and ready to absorb
the ink.
Screen frame.
The screen frame is usually made
of wood and is very tightly covered with a fine
mesh material. This is the screen through which
the ink is transferred onto the object to be printed.
Metal screens are the most durable and stand
up to many washing and printings.
Black paper, plastic, or fabric. This flat black
object should be large enough on which to place the
frame is the surface on which the screen is placed
to burn the image onto the screen.
Photosensitive Emulsion and Activator. The sensitizer
and Emulsion come separately and must be mixed
together and applied to the screen. Users must make sure to
Mix enough to thoroughly cover the screen. Screen printing ink. Users need to buy
enough screen printing ink to transfer the design to the object being printed. It might be
fun to choose several different colors and make several versions of the screen print art.
Squeegee. A squeegee is an important tool in screen printing. It is used to apply and
spread the ink through the screen onto the T- shirt or other object. Squeegees are
available in several different sizes, and they are made from a single piece of vinyl or
from a comfortable wooden holder with a rubber blade.
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C. Prepare the frame and screen
Some people make their own mesh screens for printing by
taking an old wooden picture frame and covering it tightly with an organdy silk screen
fabric, or even cut- up old gauzy nylon curtains. Users should make sure that the fabric
is stretched as tight as possible and is secured thoroughly with a staple gun applied all
around the frame. It is important to keep the fabric straight so that the holes in the mesh
of the fabric allow the ink to pass through it evenly.
A commercially prepared screen that has already been used
should be prepared for printing by washing it thoroughly with a mild abrasive to ensure
that none of the holes are clogged with dirt, grease, or previously used ink. The screen
should also be allowed to dry thoroughly.
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D. Spread the photo emulsion onto the
screen
First, users should mix the sensitizer and the
emulsion thoroughly according to the directions on the containers. The emulsions are
light- sensitive liquid chemicals that are applied to the screen, and they become more
sensitive as they dry.
The side of the screen that comes in contact with the object to be printed is known as
the substrate side, while the side where the ink is placed and pushed through the
screen is called the “inkwell” side. Both side need to be covered with the emulsion
mixture, and it is best to begin on the substrate side. Some people prefer to place the
screen on top of a piece of black fabric or plastic. Users should pour some it thinly and
evenly, making sure that all of the holes are covered.
Next, users should place the screen in a dark place to dry (a closet works well). Some
people like to point a fan at the screen to help it dry faster. Users need to make sure
that the emulsion on the screen has dried completely, and this can take as little as a
couple of hours or as long as overnight.
E. Burn the images onto the screen.
The next steps are to attach the artwork to the screen and
expose it all to light in order to burn the images onto the screen, so that the ink can
pass through the screen and be transferred to the object being printed.
Attaching the Artwork.
Once the emulsion on the screen is completely dry, users
should lay it down on top of a clean piece of black cloth or sturdy paper, with the
substrate side facing down and the inkwell side facing up. They should then lay the
template with the design on it down on the inkwell side of the screen and attach it with
tape. Alternatively, they could also lay a piece of clean glass on top of the artwork, while
making sure that the glass is bigger than the design while still fitting inside the frame.
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24. 19
If the emulsion being used is highly photosensitive, it may be
best to do this step in a fairly dark room so that the emulsion does not begin to react to
the light until the artwork is securely in place.
Exposing the screen to light.
Next, they should place a lamp with a 200- or 250- watt bulb
about a foot or two above the screen. Professional screen printing lamps are also
available for purchase, while some people like to take the frame with the artwork
attached outdoors so that the UV rays of the sun burn the images. With the exposure to
light, the emulsion hardens, and the area of the screen that is covered by the design
does not harden. Usually 10 to 15 minutes is enough time for this process to be
complete.
F. Rinse the screen
Once the photosensitive emulsion has hardened, users should
remove the artwork and rinse the screen under very cold water. This can be done in a
shower or tub, or outdoors with a garden hose. The emulsion that was under the design
flakes off. It may be necessary to gently rub the area where the emulsion is being
removed, using a hand or the scratchy side of a kitchen sponge . once the screen is
thoroughly rinsed, the design should be visible as a see- through part of the screen, like
a stencil made out of mesh.
G. print
For the printing stage, it is a good idea to put masking tape or
painter`s tape along the edges of the screen to prevent any sloppy leaks. Users should
place the fabric or object to be printed down on some newspapers to protect the surface
underneath. It is important to work on a flat surface so that the images is not distorted.if
it is a T- shirt that is being printed, users can place some layers of paper or cardboard
inside the shirt to prevent the ink from leaking through to the other side of the shirt.
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When users are ready to begin the printing process, they can lay
the screen down with the substrate side touching the fabric to be printed. Next, they can
pour a small amount of ink horizontally across the top of the screen and use a
squeegee to pull the ink down across the image, pressing the ink through the screen
onto the fabric underneath. They can then move the squeegee up and down and back
and forth to ensure that the ink is pressed through the screen thoroughly and evenly.
The screen should be held in place, or else the images may not comes through crisply.
At this point, the artwork should be in printed form.
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H. Cure and clean up
Some screen printing ink manufactures recommend
“curing”, which is placing the printed object in an oven preheated to 400 degrees F for
just about 30 seconds. Other ink makers recommend ironing the back of the printed
fabric to help set the ink. Users should be sure to follow the manufacturer
recommendations on the ink being used.
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PRINTING
PASTE
PREPARATION
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Printing Process:
Printing, like dyeing, is a process for applying colour to a substrate. However, instead
of colouring the whole substrate (cloth, carpet or yarn) as in dyeing, print colour is
applied only to defined areas to obtain the desired pattern. This involves different
techniques and different machinery with respect to dyeing, but the physical and
chemical processes that take place between the dye and the fibre are analogous to
dyeing.
A typical printing process involves the following steps:
Color paste preparation:
When printing textiles, the dye or pigment is not in an aqueous liquor, instead, it is
usually finely dispersed in a printing paste, in high concentration.
Printing:
The dye or pigment paste is applied to the substrate using different techniques, which
are discussed below.
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Fixation:
Immediately after printing, the fabric is dried and then the prints are fixed mainly with
steam or hot air (for pigments). Note that intermediate drying is not carried out when
printing carpets (too much energy would be needed for removing the highly viscous
liquor).
After-treatment:
This final operation consists in washing and drying the fabric (it is not necessary when
printing with pigments or with other particular techniques such as transfer printing).
When describing the different printing techniques, a distinction should be made
between printing with pigments, which have no affinity for the fibre, and printing with
dyes (reactive, vat, disperse, etc.).
Printing with Pigments:
Pigment printing has gained much importance today and for some fibres (e.g.
cellulose fibres) is by far the most commonly applied technique. Pigments can be used
on almost all types of textile substrates and, thanks to increased performance of
modern auxiliaries, it is now possible to obtain high-quality printing using this technique.
Pigment printing pastes contain a thickening agent, a binder and, if necessary, other
auxiliaries such as fixing agents, plasticizers, defoamers, etc.
White spirit-based emulsions, used in the past as thickening systems, are used only
occasionally today (mainly half-emulsion thickeners). More information regarding the
characteristics of the auxiliaries used can be found in Section.
After applying the printing paste, the fabric is dried and then the pigment is normally
fixed with hot air (depending on the type of binder in the formulation, fixation can also be
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30. 25
achieved by storage at 20 °C for a few days). The advantage of pigment printing is that
the process can be done without subsequent washing (which, in turn, is needed for
most of the other printing techniques).
Printing with Dyes:
Printing paste preparation:
The process traditionally starts with the preparation of the paste. Compared to pigment
printing, the composition of the pastes is more complex and variable, being determined
not by the dye used, but by the printing technique, the substrate, the application and the
fixation methods applied.
Apart from the dye, printing pastes contain a thickening agent (see also Section) and
various other auxiliaries, which can be classified according to their function as follows:
 Oxidizing agents (e.g. m-nitrobenzenesulphonate, sodium chlorate, hydrogen
peroxide)
 Reducing agents (e.g. sodium dithionite, formaldehyde sulphoxylates, thiourea
dioxide, tin(II) chloride)
 Discharging agents for discharge printing (e.g. anthraquinone) Substances with a
hydrotropic effect, like urea.
 Dye solubilisers, which are polar organic solvents like glycerine, ethylen glycol,
butyl glycol, thiodiglycol, etc.
 Resists for reactive resist printing (e.g. sulphonated alkanes).
 Defoamers, (e.g. silicon compounds, organic and inorganic esters, aliphatic esters,
etc.).
All the necessary ingredients are metered (dosed) and mixed together in a mixing
station. Since between 5 and 10 different printing pastes are usually necessary to print
a single pattern (in some cases up to 20 different pastes are applied), in order to reduce
losses, due to incorrect measurement, the preparation of the pastes is done in
automatic stations. In modern plants, with the help of special devices, the exact amount
of printing paste required is determined and prepared in continuous mode for each
printing position, thus reducing leftovers at the end of the run.
It is common practice in many printing houses to filter the printing pastes before
application, using for example a filter cloth. This operation is especially important for
thickeners to prevent free particles from blocking the openings of the screens.
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PRINTING
PASTE
(APPLICATION)
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After preparation, the paste is applied to specific areas of the textile using one of the
following techniques:
1. Direct printing (which also includes digital and transfer printing)
2. Discharge printing
3. Resist printing.
 In the case of direct printing the dye is applied to specific areas of a pretreated
textile substrate, which can be white or pre-dyed (in light colours).
 It is possible to speak of discharge printing, if in the fixation process that follows the
application of the printing paste there is local destruction of a dye applied
previously. If the etched (discharge), previously dyed area becomes white, then the
process is called white discharge. If, on the contrary, a coloured pattern has to be
obtained in the etched area after the destruction of the previously applied dye, then
the process is called coloured discharge. In this case the printing paste must
contain a reduction-resistant dye along with the chemicals needed to destroy the
previous one. As a result the pre-dyed background is destroyed according to a
pattern and the dye, which is resistant to reduction, takes its place.
 In the case of resist printing, a special printing paste (called «resist») is printed onto
certain areas of the fabric to prevent dye fixation. In the case of physical resist the
material is printed with a difficult-to-wet resin that inhibits the penetration of a dye
applied in a second stage. On the other hand, with a chemical resist, dye fixation is
prevented by a chemical reaction. Depending on the way the process is carried out,
one can speak of pre-printing, intermediate or over-printing resists. One common
procedure is the wet-on-wet process in which the resist paste is initially printed,
then the material is overprinted with full cover screen and finally fixed and washed.
Over-printing resists can be applied only if the dye, already present in the
previously dyed and dried fabric, is still in its unfixed form, as in the case of
developing dyes.
 The difference between transfer printing and the techniques described earlier is that
with this technique the surface of the fabric is not directly printed. Instead, the
pattern is first created on an intermediate carrier (e.g. paper) using selected
disperse dyes and then it is transferred from there to the fabric. The dye is usually
fixed by placing the printed paper in contact with the fabric into a thermal pressure
system. Under the influence of the heat the dye sublimates and diffuses from the
carrier into the fibre of the textile substrate. There is no need for further treatment
such as steaming, washing, etc. This technique is applied for polyester, polyamide
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and some acrylic fibres, using selected disperse dyestuffs according to the specific
type of fibre.
Fixation:
After printing, the fabric is dried. Water evaporation leads to an increase in dye
concentration and at the same time prevents the colours from smearing when the fabric
is transported over the guide rollers. At this stage the dye is not yet fixed.
The aim of the subsequent fixation step is to transport as much as possible of the dye,
which is retained by the thickener, into the fibres. This is especially important with dyes,
such as vat dyes, for example, that are printed in the insoluble form and are converted
into the corresponding soluble state only after reaction with the reducing agents during
the fixation process.
Fixation is usually carried out with steam. Water vapour condenses on the printed
material, swells up the thickener, heats the print and provides the necessary transport
medium for the diffusion of the dye. The distribution of the dye between fibre and
thickener is an important factor in determining the fixation degree of the dye, which is
called the "retaining power" of the thickener. The thickener, in fact, is often composed of
polysaccharides and therefore competes with cellulose in retaining the dye. This is the
main reason why the fixation rate of a given dye is 10 % lower in printing than in
dyeing.
After-treatment:
The last step of the printing process consists in washing and drying the fabric. When
printing with insoluble dyes such as vat dyes this operation also serves as a means to
re-convert the dye to the original oxidised state. In this case, after an initial rinsing with
cold water, the printed material is treated with hydrogen peroxide. The process is
completed with a soap treatment with sodium carbonate at the boiling point.
As already explained, washing is not necessary with pigment printing and transfer
printing. This holds for any dyeing/ printing system where thickeners are not needed
and where the dyestuff is (nearly) completely fixed (e.g. printing carpet tiles with digital
jet printing techniques, see Section).
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Printing Auxiliaries:
Auxiliaries for dye printing:
Thickening agents:
Thickening agents are essential components of printing pastes. They are responsible
for preventing capillary flow between the threads of the fabric, thus inhibiting dye
diffusion. Oil/water emulsions, used in the past as thickeners, have now been largely
replaced by formulations similar to those used for warp sizes. Standard components of
modern thickeners include natural polysaccharides, both unmodified and chemically
modified (e.g. seed derivatives, starch degradation products, alginates) and fully
synthetic polymers (mainly based on polyacrylic acid). Thanks to the improvements
made in the characteristics of the starting materials, thickening agents are now supplied
almost exclusively in cold-soluble form.
Auxiliaries for Pigment Printing:
Thickening agents:
Water-in-oil emulsions were widely used in the past as thickeners. They contained up to
70 % of white spirit (mixture of aliphatic hydrocarbons with C12-C50 chain length),
which resulted in emissions of volatile organic carbon in the exhaust air from drying and
curing ovens. Half-emulsion printing pastes (oil in water) are only occasionally
employed today. Nevertheless, modern thickeners can still contain approximately 10 %
of mineral oils, which are ultimately found in exhaust air. New generation thickeners
have been developed which do not contain any volatile solvents. They are supplied in
the form of non-dusting granules [64, BASF, 1994].
Binders:
The pigment has no affinity for the fibre. Therefore, in order to coat the pigment and
protect it from mechanical abrasion, a binder is added to the printing paste. Binders are
in general self-cross-linking polymers which reticulate during the fixation step. They are
supplied as aqueous polymer dispersions, based mainly on acrylates and less
commonly on butadiene and vinyl acetate.
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Fixing agents :
Additional fixing agents are sometimes necessary to enhance the level of wet-
fastness, especially with smooth fibres such as PES. Melamine-formaldehyde
condensates are used for this purpose. In order to reduce the consequent formaldehyde
emissions, modified compounds of the same chemical type, but with a low
formaldehyde content, are now common.
Plasticisers :
Plasticisers are mainly silicones or fatty acid esters, which are used to improve the dry
rubbing fastness and give a smooth dry handle to the fabric.
Emulsifiers:
In high- and low solvent pigment printing pastes, the emulsifiers serve to stabilise the
solvent (white spirit). In solvent-free pigment printing they are used to prevent
agglomeration of the pigment, screen blocking and separation of components of the
print paste [186, Ullmann's, 2000]. Non-ionic surfactants such as aryl- and alkyl
polyglycol ethers are the most commonly used for this purpose.
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HAND PRINTING
SAMPLES
PASTE
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APPLICATION
OF
SCREEN PRINTING
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The textile industry probably makes the largest
use of the screen printing technique. Screen printing is used to print on fabrics ranging
from cotton and organza to silk and polyester. These fabrics are then made into finished
product. The finished products include shirts, skirts, dresses, children`s clothing and any
kind of clothing made from printed the fabric. In fact many designers set up their own
screen printing units since they are so cheap.
The designer then creates his or her own design and
screen prints it in limited quantities for sale with his or her brand label. Screen printing is
also used for upholstery, linen, curtains, drapes, cushion covers, bed sheets, bedcovers
and other household and lifestyle requirements.
The other industry that makes extensive use of screen
printing is the marketing and advertising industry. Flyers, posters, handouts,
advertisement and other point of sale or graphics products are all screen printed. The
advertising industry uses screen printing primarily because it generally requires limited
edition printing. The costs of printing small quantities digitally or electronically can be
very high. Hence screen printing to the rescue.
The sports industry also uses screen printing to print
souvenirs and collectible items. T- shirts printed with the logos of popular teams,
souvenirs like caps, sweatshirts, mouse pads, key chains, baseball bats and a host of
other items are all screen printed. Thus, screen printing has innumerous applications.
Everywhere you look you will find examples of screen printing. Some are overt and
others will be disguised.
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ADVANTAGES
&
DISADVANTAGES
OF
SCREEN PRINTING
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 Advantages of Hand Screen Printing:
There are several advantages of hand screen
printing that we must have to know. These are –Less investment cost: As there is no
machine required in hand screen printing and it is possible to print in a shorter space;
the total investment in hand screen printing is comparatively lower than other screen
printing system.
No Risk: No heavier instrument or machine tools are used in hand screen printing.
So, there is no risk.
Multi-color design can be printed: In hand screen printing procedures various
colors can be used effectively.
Less floor space is required: As no heavier and bigger machines and related
tools are used, the hand screen printing want to install a screen printing factory for you
local business, you can choose the hand screen printing at the initial stages as it
requires lower cost or investment.
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 Disadvantages of Hand Screen Printing:
Besides the advantages of hand screen printing; we have
to know about the disadvantages of hand screen printing too. Because it is needed
for developing the process or solving any problems occurred during installation.
Slow production rate: As no machine is used and all of the process are done by
manually; the production rate becomes lower than other printing process.
Small scale production: If you want to own a big screen printing factory or if
you have some bigger plan in future; the printing is not for you. Due to some reason
this kind of printing process provides you lesser production rate.
Labor intensive process: A labor has to work manually and all of the process
of the hand screen printing is done by the hands. So it needs more time to produce a
product.
Fastness properties are average: As all of the process is done manually, the
fastness properties of the printed fabric is not well. Difficult to maintain even
penetration and print paste.
Skilled man- power is required.
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CANCLUSION
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Screen printing is an ancient art and is one that can be practiced by anyone
from commercial producers to casual hobbyists. Whether creating screen
printed T-shirts to sell for a school fundraiser, giving new life to a drab old
tablecloth, or simply making something beautiful to hang in a home, screen
printing can provide a creative outlet with very practical applications.
It is important for anyone who is going to attempt to do screen printing using
photosensitive chemical emulsions to understand the entire process. This
information helps artists, whether beginners or experienced, to go through
the screen printing process with confidence. It also offers helpful tips for
creating the artwork, gathering the necessary materials, preparing the screen,
applying the emulsion, burning the image, rinsing the screen, the actual
printing itself, and finally curing the finished product and cleaning up. By
following the above tips, anyone can be successful in their next screen
printing project.
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REFERENCE
https://en.wikipedia.org/wiki/Screen_printing
https://en.wikipedia.org/wiki/Screen_printing#Printing_technique
https://msdstyle.com/pages/hand-screen-printing
http://www.testextextile.com/advantages-disadvantages-of-hand-screen-
printing-in-textile-industry/
https://rebeccaatwood.com/blogs/from-the-studio/how-we-make-it-screen-
printing
http://www.vastex.com/Literature/vastex_101.pdf
http://www.inverlochy.org.nz/News-Events/ID/1580
https://blog.printsome.com/what-is-screen-printing/
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