Defects in dyeing and printing

1. BUBT
DYEING AND PRINTING PRESENTATION
DEFECTS IN DYEING AND PRINTING
Submitted by:-
Md.Ibrahim Khalil
ID:16173207095
Intake:19,Section:02
Department of Textile Engineering
Bangladesh University of Business & Technology

2. DYEING AND PRINTING
Textiles are usually coloured to make them attractive or for functional
reasons. There are two ways of adding colour to a textile substrate –
1. Dyeing
2. Printing
DYEING
Dyeing is employed to give an all-over shade to the fabric. Coloration of
Dyeing involves the use of Dye Stuff which are capable of reacting and
combing with the Textile fiber molecule, usually when in a water
solution, and usually with other auxiliary chemicals to enhance the
process.
PRINTING
Printing can be defined as localized application of dye or pigment in a
paste form to generate a pattern or design in the fabric. It is also called
localized dyeing.
KEYS TO GOODQUALITY
1. C o n s i s t e n cy
2. . U n i f o r m i t y
3. Knits - Low Tension .
4.Woven – Penetration

3. COMMON CAUSES OF DEFECTS
1. The material is not well prepared for dyeing and printing
a. Material having dead fibres or other defective fibres
b. Left over of Chemicals after bleaching etc.
c. Material not properly desized
d. Material not properly mercerised.
e. Absorbancy of the fabric not proper
f. Sticking of insoluble material on the fibres
g. Impurities are not removed properly
h. Uneven heat treatment.
2.Water Quality not Proper
a. More Hardness of water
b. Water has metal ions such as iron.
c. pH of water not proper
d. Water having more chlorine
3. Due to Shortcomings in making Dyeing Solution
a. Improper weight ratio of colors, material and chemicals.
b. Improper material to water ratio
4. Improper filtering of concentrated colors.
5. Due to Shortcomings in the dye machinery
a. Coming out of Dye liquor during dyeing
b. Defective instruments controlling temperature, pressure speed etc.

4. DYEING DEFECTS
1 . B A R R E
- Fabric will appear to have horizontal streaks. It may be caused due to
the variation in size of the filling yarn and the differences in tension
either the filling or warp yarns.
2 . C O L OU R B LE E D I N G
-
It’s a loss of colour when the dyed fabric is wetted or immersed in water.
The water become coloured and may lead to discoloration of other
fabrics.
This is usually due to either improper dye selection or poor dry fastness.

5. 3. C O L O U R C R O C K I N G
- It is the rubbing off of the colour. It may rub onto other fabric.
This may be due to inadequate scouring subsequent to dyeing.
4 . O F F S H A D E
–It refers to colour that exactly doesn’t match the standard of the
prepared sample. This may be due to faulty dye foundation or
application or may be due to variation in dye lot.

6. 5 . S H A D E B A R
-It is variation in colour tone either horizontally or vertically.
6 . S H A D E C R O S S B A R
-It is variation in colour tone either horizontally or vertically.

7. 7. C R E AS E S T R E AK
-It occurs in tubular knits. It results from creased fabric passing through
squeeze rollers in the dyeing process.
8. DYE STREAK IN PRINTING
-It results from a damaged doctor blade or a blade not cleaned properly.
Usually a long streak until the operator notices the problem.
9 . T E N D E R S P O T S
–It refers to places in the fabric that have been excessively weakened,
actually by exposure to processing of chemicals. Sulphur dyed fabrics
show Tendering.
10. UNEVEN SHADE
–It is the difference in the shade of the fabric from edge to edge or one
end of the fabric to another.
11. STAINED (UNCLEAR)
–The fabric may be stained due to various reasons such as foreign
material caught while dyeing.

8. Dyeing Remedies:
->By ensuring even pretreatment.
->By ensuring even heat-setting in
case of synthetic fibers.
->Proper dosing of dyes and
chemicals.
->Proper controlling of dyeing m/c-
->Use standard dyes and chemicals.
->Maintain the same liquor ratio.
->Follow the standard pretreatment-
procedure.
->Maintain the same dyeing cycle.

9. ->By ensuring proper
pretreatment.
->Proper dosing of dyes and
chemicals.
->Heat should be same
throughout the dye liquor.
->Proper salt addition.
->Use standard dyes and
chemicals.
->Proper m/c speed.
->Use of soft water.

10. PRINTING DEFECTS
B L E B B I N E S S
-A part of printed surface becomes blebby with a rough appearance like
that of sharkskin. It occurs due to unsuitability of colour paste viscosity
and screen mesh and uneven adhesion.
B L E E D I N G
–A printed motif blurs and as a result the outline of the design appears
unclear. This may be due to – the viscosity of the colour paste is too low,
the concentration of the dyestuff in the print paste is too high and the
amount of colour paste printed or the amount of hygroscopic agent used
id too high

11. STAINING DURING STEAMING
–Stains are transferred when a poorly washed printing table is used, the
printing cloth is piled up after insufficient drying or a part of the cloth
touches another during steaming
U N E V E N PR I N T I N G
–Colour tone gaps appear horizontally at the same distance from each
other. This may be due to bad screen frame, a poorly installed squeegee and
uneven squeegee pressure

12. S LI G H T T O U C H I N G
–Some area in the motif has pale spots. This may be due to slow
replenishment of colour paste, uneven squeegee pressure, choosing a
squeegee within appropriate hardness, bad squeegee relay, and uneven
surface of printing table, inappropriate viscosity of the colour paste and
inappropriate use of thickener
POORLY ADJUSTED SCREEN
–Disfigured designs or overlapped motifs. This is due to the belt drive
and point adjustments, etc are not properly done

13. D O U B LE PR I N T I N G
–Designs printed are a little off. Disfigured designs, poor engraving,
poor cloth adhesion, etc are the cause of this problem
PRESSING PASTE BY FRAME
–Sometimes a frame mark appears in the printed area. This is because of
poor belt drive and frame installation.

14. PATTERN BENDING
–When the print bends or is of different width in different areas.
SPECK
–Dots are visible due to colour stain. This might occur due to non-
dissolved dye stuff and impurities contained in colour paste have fixed
to the problem area.

15. STAIN DUE TO FRICTION
–Staining occurs since the motif touches something when it is not dried
and scuffed after all.
COLOR SMEAR/COLOUR PASTE SPLASH
It is the result of colour being smeared during printing. The splashes are
most likely to occur when the roller printing speed is too fast, the screen
plate is lifted inappropriately or the viscosity of the colour paste is too
low.

16. EXTRA HANGING YARNS
–Yarns like stains are made by the extra hanging yarns sticking out of the
cloth. This happens when poorly knit fabric is used.
LISTING
–The colour shade or depths of selvedges are different from that of the
center. This happens due to poor bleaching, poor installation of a frame
and squeegee, uneven squeegee pressure and inappropriate padding and
colour fixing.

17. END STITCHES STAIN
–Stain made by sewing machine stitches or the end stitches of the under
cloth. This happens when the end stitches or joints overlap end up too
large.
DROPS
–Stains or unevenness due to drops. Drain (condensed water) or drops
are the cause.

18. DOCTOR MARK
–Belt-like-stain appears vertical to the direction of roller printing.
CREASE MARK
-differs from crease streak in that streak will probably appear for an
entire roll. Crease mark appears where creases are caused by fabric folds
in the finishing process. On napped fabric, final pressing may not be
able to restore fabric or original condition. Often discoloration is a
problem.

19. POOR DISCHARGE/ RESIST PRINTING
–Poor white discharge and colour discharge have to do with poor
conditions of discharge/resist printing paste, colour paste, squeegee
pressure, steaming.
CRACK OF PRINT PASTE
–Printed colour paste cracks. The problem occurs because poor
treatment is carried out after printing or the viscosity of the colour paste
is inappropriate.

20. ROPE MARK MODIFICATION
–Rope and roller leave their mark son printed cloth. This is when the
temperatures during steaming are too high or the temperatures set for
finishing are toolow.
ROPE MARKFADING
–The area that has touched rope or rollers during steaming has faded
colours or stains. This problem occurs particularly when steam is
condensed in rope or rollers.

21. CLIP AND PIN MISS
–Tenter’s pin or clip marks remain or appear too inside. Bad clips or
pins, poorly conditioned guilder and unusual cloth width can lead to the
problem.
UNPRINTED AREA
–Some area in a motif are not printed. The reason is that a foreign matter
has been built up in the screen mesh, or the colour paste cannot adhere to
the cloth. It occurs for example in printing a fabric with slubs or by fuzz

22. balls in the printing paste. Imprint is created by touching insufficiently
dried right side of the print.
CRACK MARKS
–Unprinted part appears when the fabric is stretched or bent. This is
caused by poor penetration of colour paste due to inappropriate viscosity
of colour paste, screenmeshandsqueegeepressure.
MOIRE
–Moiré patterns appear on printed designs. Screen mesh, the roulettes of
routers, the line delineation pattern has to do with this phenomenon.

23. WATERMARK
–An unwanted ripple effect/light mark produced on the fabric. Main
causes are improper scouring, surface pressure of one fabric on another,
contamination with water prior to tinting or dyeing on the pad mangle
resulting in the reduction in the uptake of dye liquor.
STAINED
–It indicates a discoloration caused by a foreign substance, grease, and
oil or sizing residue on the fabric being dyed.
DEFECTIVE REGISTER
-knitting repeat is a shift of one or more repeats of a printed pattern,
colours and lines of the resulting printing overlap.
BACK FABRIC SEAM IMPRESSION
-backing fabric is often used to cushion fabric being printed. If there is a
joining seam in the backing fabric, an impression will result on printed
fabric
COLOR OUT
- the result of colour running low in reservoir on printing machine.

24. Printing Remedies:
-> High viscosity of print paste.
->Proper alignment of the screens.
-> Color applied evenly during printing
->Proper printing procedure

25. COMMON REMEDIES FO DYEING
AND PRINTING DEFECTS:

26. Thank You