Textile Printing
Itistheprocessofapplyingcolourtofabricindefinitepatternsordesigns.
In properly printed fabrics the color is bonded with the fiber, so
as to resist washing and friction. Textile printing is related to
dyeing but, whereas in dyeing properthe whole fabric is uniformly
covered with one color, in printing one or more colors are applied
to it in certain parts only, and in sharply defined patterns.The
main objectives of textile printings are the production of
attractive designs with well defined boundaries made by the
artistic arrangement of a motif or motifs in one or more colors.
Printed fabrics are well protected from friction and washing if
dyes or pigments are applied properly on fiber. A strong bonding is
formed between dyes and fibers.Steps in textile printing:Textile
printing is carried out in different steps, such as: At first,
fabrics should be pre-treated before printing. Printing paste must
be prepared by using printing ingredients; printing performance
depends on a well printing paste. Then, making an impression of the
print paste on the fabric by using any of the printing methods,
which is required. After that, drying is carried out on printed
fabric. Steaming is carried out on printed fabric for fixing the
printing paste on the fabric. At last, printing fabrics are
neutralized by the after-treatment process.
History of Textile Printing:Early forms of textile printing are
stencil work, highly developed by Japanese artists, and block
printing. In the latter method a block of wood, copper, or other
material bearing a design in intaglio with the dye paste applied to
the surface is pressed on the fabric and struck with a mallet. A
separate block is used for each color, and pitch pins at the
corners guide the placing of the blocks to assure accurate
repeating of the pattern. In cylinder or roller printing, developed
c.1785, the fabric is carried on a rotating central cylinder and
pressed by a series of rollers each bearing one color. The design
is engraved on the copper rollers by hand or machine pressure or
etched by pantograph or photoengraving methods; the color paste is
applied to the rollers through feed rollers rotating in a color
box, the color being scraped off the smooth portion of the rollers
with knives.More recent printing processes include screen printing,
a hand method especially suitable for large patterns with soft
outlines, in which screens, one for each color, are placed on the
fabric and the color paste pressed through by a wooden squeegee;
spray printing, in which a spray gun forces the color through a
screen; and electro coating, used to apply a patterned pile. Color
may be applied by the various processes directly; by the discharge
method, which uses chemicals to destroy a portion of a previously
dyed ground; or by the resist, or reserve, method, which prevents
the development of a subsequently applied color to a portion of the
fabric treated with a chemical or with a mechanical resist.
Styles of Printing:A process for producing a pattern on yarns,
warp, fabric, or carpet by any of a large number of printing
methods. The color or other treating material, usually in the form
of a paste,is deposited onto the fabric which is then usually
treated with steam, heat, or chemicals forfixation.There are three
different printing'styles' used to produce patterned effects on
textiles, these being termed direct, discharge and resist. Each of
these will be described in turn.
Direct Printing Style
This method involves the direct application of the color design
to the fabric and is the most common method of textile printing.
The dyes used for direct printing are those which would normally be
used for a conventional dyeing of the fabric type concerned.
Discharge PrintingStyleIn this method the fabric is pre-dyed to
a solid shade by a traditional dyeing process and the color is then
destroyed locally, by chemicals incorporated in the print paste
especially for that purpose. The result is a white patterned
discharge on a colored ground.In white discharge printing, the
fabric is piece dyed, then printed with a paste containing a
chemical that reduces the dye and hence removes the color where the
white designs are desired. In colored discharge printing, a color
is added to the discharge paste in order to replace the discharged
color with another shade.
Resist PrintingStyle
In this method of printing the fabric is first printed with a
substance called a 'resist' which will prevent the dye from being
taken up in a subsequent dyeing process. The resist functions by
either mechanically preventing thedye from reaching local areas of
the fabric or by chemically reacting with the dye or the fiber, to
prevent adsorption.A printing method in which the design can be
produced: (1) by applying a resist agent in the desired design,
then dyeing the fabric, in which case, the design remains white
although the rest of the fabric is dyed; or (2) by including a
resist agent and a dye in the paste which is applied for the
design, in which case, the color of the design is not affected by
subsequent dyeing of the fabric background.
Methods of Printing:There are several methods of printing; the
main methods are as follows:
BLOCK PRINTINGBlock printing is a printing technique for
producing patterns by means of carving a design into a wooden
block. The raised part is coated with ink and prints the design on
fabric or paper which is similar to modern day stamping. It is the
oldest form of printing known to man and has since been replaced by
silk screening.Block Printing is one of the oldest types of
printmaking, and has been around for thousands of years. There is
evidence that it existed as early as the fifth century BC, with
actual fragments found from as early as the fifteenth century. It
has been done around the world, with roots in India, China and
Japan.Since there is such a long history of block printing, there
are many different techniques, but it is essentially using a carved
material covered in ink to transfer an image on to paper or fabric.
Block printing can be done with wood, linoleum, rubber, or many
other materials, but we use linoleum for this work.Images that are
printed with this technique are typically much bolder than other
types of printmaking: since the blocks are carved by hand, there is
often less detail and more texture to the prints. It is possible
however, when using a very small knife, to carve blocks with a huge
amount of detail.Block printing is also known as relief printing
because the ink leaves a raised texture on the paper. This is
different than letterpress where the image is applied with enough
pressure to leave an indent on the paper; typically block printing
is done by hand, so the ink sits on the surface adding a raised
texture to the paper.
The Printing ProcessThe first step is to sketch the design. It
is important to reverse the image if you are using text, as the
printed image will be the reverse of what is on the block. Once you
have the image ready, and then transfer the design on to the
linoleum to give me an outline of where to carve.The next step is
to carve the design. Carve away the parts that you dont want to
print, as the ink will be applied to the raised surfaces to print
the design. Whatever surface is untouched will be what prints onto
the paper. Carving a block can take anywhere from an hour for a
small piece, to several weeks or even months depending on the size
and detail of the image.Use a range of knives, with very
small-tipped knives for carving outlines and details, and much
larger ones for cutting away the background. Carving the blocks
takes a lot of patience, because if your hand slips it can ruin the
whole piece. With practice, you can learn the amount of pressure it
takes to carve the material, and the best techniques to use for
certain designs.
Once the block is carved, trim the excess off with scissors to
give it a straight edge, and then it is ready for printing. There
are many different types of ink on the market, and its important to
test them out to find the best one. Use oil-based inks because they
give the best even coverage and print well on both fabric and
paper, but there are lots of options out there.To print, squeeze a
small amount of ink onto a piece of glass or Plexiglas, and roll it
out with a roller (also called a brayer) to get a thin, even layer,
because its important to apply the ink evenly to the block.Then
roll the ink on to the block, making sure there is a thin but even
layer on the whole design. Then take the block and press it down
onto the paper or fabric. You can do this with your hands, a
printing barren (a specific tool to apply pressure to a block), a
rolling pin, by walking on it, or with a printing press whatever it
takes to apply even pressure.The most important part is applying
the pressure evenly, since the color will be stronger in some areas
of the print than others if uneven pressure is applied. This is
also a step that takes some practice and perfecting.The ink then
takes several days to dry, so unlike other printing processes,
there is a long wait time before the prints are ready to use. The
oil based inks can take from two days to a week to fully dry,
whereas water-based inks will dry slightly faster. The inks are
made to dry slowly so that you are able to print without having the
ink dry on the block; if you print with a fast-drying ink or paint,
it will sometimes start to dry before you have even finished the
print, giving a very uneven coverage.
Tips and AdviceBlock printing is very popular because of the
bold and simple designs that can be created, but that simplicity
takes a lot of steps to achieve. The technique is excellent for
images with just a few colors and fewer details, but can be
difficult to use for images with lots of small text, or very fine
details that tend to break off the block with too many uses.One of
the advantages of block printing is that it can be done on a
surface of almost any size and texture like fabric, paper, canvas,
wood and other materials, and you dont have to worry about fitting
it through a printer or a press.Block printing is also an excellent
way to produce a something that is truly handmade, but can be very
easily replicated. Carving the block is time consuming and requires
a lot of patience, but once you have the block you can use it
hundreds or thousands of times.Block printing is also one of the
easiest printing methods to get started with, since the materials
needed to start are relatively inexpensive, and you dont need a lot
of equipment for printing. Its a great way to get into
printmaking!
SCREEN PRINTING:
Screen-printing is the most flexible printing process. It can be
used to print on a wide variety of substrates, including paper,
paperboard, plastics, glass, metals, fabrics, and many other
materials including paper, plastics, glass, metals, nylon and
cotton.
Somecommonproductsfromthescreen-printingindustryincludeposters,labels,decals,
signage, and all types of textiles and electronic circuit boards.
The advantage of screen-printing over other print processes is that
the press can print on substrates of any shape, thickness and size.
An important characteristic of screen-printing is that a greater
thickness of ink can be applied to the substrate as compared to the
other printing techniques. This allows forvarious interesting
effects that cannot be achieved through the other printing methods.
Because of the simplicity of the application process, a wider range
of inks and dyes are available for use in screen-printing than for
use in any other printing process.
Overview of the Screen Printing Process Screen-printing consists
of three elements The screen which is the image carrier The
squeegee Ink
The screen-printing process uses a porous mesh stretched tightly
over a frame made of wood or metal. Proper tension is essential to
accurate color registration. The mesh is made of porous fabric or
stainless steel mesh.
A stencil is produced on the screen either manually or photo
chemically. The stencil defines the image to be printed in other
printing technologies this would be referred to as the image
plate.Screen printing ink is applied to the substrate by placing
the screen over the material. Ink with a paint-like consistency is
placed onto the top of the screen. Ink is then forced through the
fine mesh openings using a squeegee that is drawn across the
screen, applying pressure thereby forcing the ink through the open
areas of the screen. Ink will pass through only in areas where no
stencil is applied, thus forming an image on the printing
substrate. The diameter of the threads and the thread count of the
mesh will determine how much ink is deposited onto the
substrates.
Many factors such as composition, size and form, angle, pressure
and speed of the blade (squeegee) determine the quality of the
impression made by the squeegee. At one time most blades were made
from rubber, which, however, is prone to wear and edge nicks and
has a tendency to warp and distort. While blades continue to be
made from rubbers such as neoprene, most are now made from
polyurethane, which can produce, as many as 25,000 impressions
without significant degradation of the image.
Screen preparation:Screen (or image transfer) preparation
includes a number of steps. First the customerprovides the screen
printer with objects, photographs, text, ideas, or concepts of what
they wish to have printed. The printer must then transfer a
"picture" of the artwork to be printed into an image which can then
be processed and eventually used to prepare the screen stencil.
Once the artwork is transferred to a positive image that will be
chemically processed onto the screen fabric (applying the emulsion
or stencil) and eventually mounted onto screen frame that is then
attached to the printing press and production begins.The silk
screen is a wooden or aluminum frame with a fine nylon or silk mesh
stretched over it. The mesh is coated with a light sensitive
emulsion or film, which - when dry - will block the holes in the
mesh. The image that needs to be printed is output to film
eitherbycameraorimagesetter.Thisfilmpositiveandthemeshonthescreenaresandwiched
together and exposed to ultraviolet light in a device called a
print-down frame. The screen is then washed with a jet of water
which washes away all the light sensitive emulsion that has not
been hardened by the ultraviolet light. This leaves you with an
open stencil which corresponds exactly to the image that was
supplied on the film.Next the fabric to be printed is pinned on a
wooden table so that it is evenly stretched and there are no
ripples.Alternatively a wax table is used. The surface of the table
is covered with wax. Below there are a network of pipes through
which steam is passed. This causes the wax to soften and the fabric
is just firmly pressed on to the
table.Thewoodenframeofthescreenisfittedwithmetalhandleswhichwillfitontotocorrespondingwoodenprotrusions
on the table. This is to aid placement, when two or more colors are
being used. Thedye ispoured onthe screenArubber blade with awooden
handle isfirmly pulled across the top of thescreen; it pushes the
ink through the mesh onto thesurface of the fabric which is being
printed. Another person stands at the other side of the table. He
takes hold of the rubber blade and repeats the process. Since the
nonprinting areas on the silk screen are blocked out, the ink is
pushed through only the porous areas corresponding to the design
and is thus transferred to the fabric.
Ifmorecolorsareused,theprocessisrepeatedwithanotherscreenandcolor.Thescreen
is always washed with a lot of water immediately after use. If this
is not done, the dye dries on the screen and clogs up the
design.
Flatbed Screen Printing
In flat bed screen printing, this process is an automated
version of the older hand operated silk screen printing. For each
color in the print design, a separate screen must be constructed or
engraved. If the design has four colors, then four separate screens
must be engraved. The modern flat-bed screen-printing machine
consists of an in-feed device, a glue trough, a rotating continuous
flat rubber blanket, flat-bed print table harnesses to lift and
lower the flat screens, and a double-blade squeegee trough. The
in-feed device allows for precise straight feeding of the textile
fabric onto the rubber blanket. As the cloth is fed to the machine,
it is lightly glued to the blanket to prevent any shifting of
fabric or distortion during the printing process. The blanket
carries the fabric under the screens, which are in the raised
position. Once under the screens, the fabric stops, the screens are
lowered, and an automatic squeegee trough moves across each screen,
pushing print paste through the design or open areas of the
screens. Remember, there is one screen for each color in the
pattern. The screens are raised, the blanket precisely moves the
fabric to the next color, and the process is repeated. Once each
color has been applied, the fabric is removed from the blanket and
then processed through the required fixation process. The rubber
blanket is continuously washed, dried, and rotated back to the
fabric in-feed area. The flat-bed screen process is a
semi-continuous, start-stop operation. Flat screen machines are
used today mostly in printing terry towels.
Advantages
large repeats
Multiple strokes for pile fabrics
Disadvantages
Slow
No continuous patterns
Productivity:
From a productivity standpoint, the process is slow with
production speeds in the range of 15-25 yards per minute.
Additionally, the method has obvious design limits. The design
repeat size is limited to the width and length dimensions of the
flat screen. Also, no continuous patterns such as linear stripes
are possible with this method. However, this method offers a number
of advantages. Very wide machines can be constructed to accommodate
fabrics such as sheets, blankets, bedspreads, carpets, or
upholstery. Also, this technique allows for multiple passes or
strokes of the squeegee so that large amounts of print paste can be
applied to penetrate pile fabrics such as blankets or towels.
Currently, approximately 15-18% of printed fabric production
worldwide is done on flat-bed screen machines.
Rotary printing:Rotary screen printing is so named because it
uses a cylindrical screen that rotates in a fixed position rather
than a flat screen that is raised and lowered over the same print
location. Rotary presses place the squeegee within the screen.
These machines are designed for roll-to-rollprinting on fabric
ranging from narrow to wide-format textiles.
In rotary printing, the fabric travels at a consistent speed
between the screen and a steel or rubber impression roller
immediately below the screen. (The impression roller serves the
same function as the press bed on a flatbed press.) As the fabric
passes through the rotary unit, the screen spins at a rate that
identically matches the speed of substrate movement.The squeegee on
a rotary press is in a fixed position with its edge making contact
with the inside surface of the screen precisely at the point where
the screen, substrate, and impression roller come together . Ink is
automatically fed into the center of the screen and collects in a
wedge-shaped well formed by the leading side of the squeegee and
the screens interior surface. The motion of the screen causes this
bead of ink to roll, which forces ink into stencil openings,
essentially flooding the screen without requiring a flood bar. The
squeegee then shears the ink as the stencil and substrate come into
contact, allowing the ink to transfer cleanly to the material.By
converting the screen-printing process from semi-continuous to
continuous, higher production speeds are obtained than in flat bed
printing. Typical speeds are from 50-120 yards per minute for
rotary screen printing depending upon design complexity and fabric
construction. Rotary screen machines are more compact than flat
screen machines for the same number of colors in the pattern.
Therefore, they use less plant floor space.Also with rotary
screens, the size of the design repeat is dependent upon the
circumference of the screens. This was initially seen as a
disadvantage, because the first rotary screens were small in
diameter. However, with todays equipment, screens are available in
a range of sizes and are no longer considered design limited.
Todays rotary screen machines are highly productive, allow for the
quick changeover of patterns, have few design limitations, and can
be used for both continuous and discontinuous patterns.
Productivity:Estimates indicate that this technique controls
approximately 65% of the printed fabric market worldwide. The
principle disadvantage of rotary screen printing is the high fixed
cost of the equipment. The machines are generally not profitable
for short yardages of widely varying patterns, because of the
clean-up and machine down time when changing patterns. Flat screen
printing is much more suitable for high pile fabrics, because only
one squeegee pass is available with rotary screen. However, rotary
machines are used for carpet and other types of pile fabrics. Most
knit fabric is printed by the rotary screen method, because it does
not stress (pull or stretch) the fabric during the process.The
rotarygarmentscreen printing machine, developed in the 1960s, is
the most popular device for screen printing in the industry. Screen
printing on garments currently accounts for over half of the screen
printing activity in the United States.
Advantages Fast Quick change over of pattern Continuous
patternDisadvantages Design limitations Small repeats
Transfer Printing:Transfer printing is the process of putting
images onto a special paper and then using that printed paper to
transfer the images to your fabric with a hot iron or hot press.
Heat transfer is great for producing clear and very well defined
images.
Supplies Plain cotton T-shirt. T-shirt transfer paper. Some cool
graphics. (You can use whatever you like here.) A printer (ink jet
not laser jet). An iron, with the steam setting switched off. A
hard surface, with a couple of tea towels on top. Note:notan
ironing board as this is too soft for the transfer to take
properly.
Once youve gathered all your supplies, its really very simple to
transfer the print onto the T-shirt. The instructions that follow
work with the transfer paper , but obviously check the instructions
on your paper before you go ahead.
Process
1. Practice printing your graphic out onto normal printer paper
first. You want to make sure you know which side of the paper your
printer is using, that the graphic is the right size for your
T-shirt and that it looks how youd like it to once its printed out.
Put the white paper over the T-shirt and make sure it all looks
right. Its also worth pointing out that your final graphic will
appear as a mirror image of the one in front of you, so make sure
it looks okay this way round. (If youve got words in your image,
you can use the mirror setting on your printer, though this might
not give as clean a print as normal.) But at this stage, experiment
and make sure youre completely happy with your results before you
put it onto the transfer paper.2. Print!3. Cut round the details of
the graphic as closely as you can. Try and remove as much of the
area that has nothing on as possible.4. Line up your image onto the
T-shirt. The clear side with the print on should face the fabric,
the white side with the squares faces out. Check and check again
that its straight and just as you want it to be.5. Iron the paper
for around two minutes. Make sure the steam setting is not switched
on. Concentrate on the centre first and then work your way out to
the sides.6. Let the paper cool down.7. Carefully and slowly remove
the white backing, starting at one of the edges and pulling it off
evenly.8. Admire your creation
From a distance, and away from direct light, the T-shirts look
great. Every little detail of the pattern has been transferred,
crisp and clear onto the T-shirt fronts.But up close, or in the
light, the area where the transfer has been ironed is really shiny
and stiff, to the point of being reflective. That area has also
lost any stretch, so it sits stiff and solid even when its being
worn. Overall, it definitely looks amateur.Because we used an image
that has lots of black lines with white space behind it, those
areas which should appear neutral show up shiny. This method would
work far better for transferring on a solid block image, probably
with color, rather than one that any blank spaces in. Then, youd
need to cut exactly round the image you had and youd eliminate this
problem of shiny areas where nothing is happening.You will reassess
once theyve been through the wash a few times, as that might help
soften it up a bit, try to use solid image to prevent from this
problem.
Advantages High quality print Fewer seconds Economical for short
runs Pollution free
Disadvantages: Slow process Primarily for polyester
Other Methods Of Printing:Stencil PrintingThe design is first
cut in cardboard, wood or metal. The stencils may have fine
delicate designs or large spaces through which color is applied on
the fabric. Its use is limited due to high costs involved..
Blotch PrintingIt is a direct printing technique where the
background color and the design are both printed onto a white
fabric usually in a one operation. Any of the methods like block,
roller or screen may be used..
Airbrush (Spray) PaintingDesigns may be hand painted on fabric
or the dye may be applied with a mechanized airbrush which blows or
sprays color on the fabric.
Electrostatic PrintingA dye- resin mixture is spread on a screen
bearing the design and the fabric is passed into an electrostatic
field under the screen. The dye-resin mixture is pulled by the
electrostatic field through the pattern area onto the fabric.
Photo PrintingThe fabric is coated with a chemical that is
sensitive to light and then any photograph may be printed on
it.
Differential
PrintingItisatechniqueofprintingtuftedmaterialmadeofyarnshavingdifferentdyeingproperties
such as carpets. Up to a ten color effect is possible by careful
selection ofyarns, dyestuffs and pattern.
Warp PrintingIt is roller printing applied to warp yarns before
they are woven into fabric.
Tie DyeingFirm knots are tied in the cloth before it is immersed
in a dye. The outside of the immersed portion is dyed but the
inside is not penetrated. There are various forms of Tie-dyeing
like Ikat Dyeing where bundles of warp and/ or weft yarns are tie
dyed prior to their weaving. In Plunge Dyeing the gathered, folded
or rolled fabric is usually held with stitching to form specific
patterns.
Batik DyeingIt is a resist dyeing process. Designs are made with
wax on a fabric which is then immersed in a dye. The unwaxed
portion absorbs the color.
Jet Spray
PrintingDesignsareimpartedtofabricsbysprayingcolorsinacontrolledmannerthrough
nozzles.
Digital printingIn this form of printing micro-sized droplets of
dye are placed onto the fabric through
aninkjetprinthead.Theprintsystemsoftwareinterpretsthedatasuppliedbyacademic_Textiledigitalimagefile.The
digital imagefile hasthe datatocontrol the droplet output so that
the image quality and color control may be achieved. This is the
latest development in textile printing and is expanding very
fast.
Conclusion:
At the initial stage of printing, the printing work was done by
hand but day by day this style is changing by utilizing different
modern techniques. Now different types of critical printing is done
very easily by the bless of modern science. Most of the printing
machines are controlled by the computer. Graphic design is mostly
use in printing process. Different types of textile machine
manufacturing companies trying to improve the present techniques of
printing methods.Anyhow, printing process plays an important role
in the civilized world. Multiple colors can be use in printing
process. Sometimes printing properties show the identity of a
nation. So, we should give great emphasis on printing process to
produce different types of attractive designs on textile
material.
BIBLIOGRAPHY
file:///D:/report/Block%20Printing%20Basics%20-%20TopTenREVIEWS.htm
file:///D:/report/The%20Printing%20Process%20%20Block%20Printing%20%20%20Oh%20So%20Beautiful%20Paper.htm
file:///D:/report/textiles%20%20The%20Printing%20of%20Textiles%20%20%20Infoplease.com.htm
file:///D:/report/Technological%20Advances%20in%20Rotary%20and%20Flatbed%20Printing.htm
file:///D:/report/Heat%20Transfer%20Printing%20-%20Wisconsin%20Screen%20Process.htm
file:///D:/report/Different%20types%20of%20textile%20printing%20processes.htm
file:///D:/report/Textile%20Printing%20%20%20Definition-Styles%20and%20Methods%20of%20Printing%20%20%20Textile%20Fashion%20Study.htm
file:///D:/report/How%20does%20the%20heat%20transfer%20process%20work%20%20-%20Local%20Hero.htm
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