CHENNAI

DEPARTMENT OF FASHION TECHNOLOGY

DYEING AND PRINTING ASSIGNMENT

DEFECTS IN DYEING AND PRINTING

SUBMITTED TO:

MR. D. PRAVEEN NAGARAJAN

ASSISTANT PROFESSOR

NIFT CHENNAI

SUBMITTED BY:

SARTHAK SAGAR

B/AP/12/1640, SEMESTER - III

DEPARTMENT OF FASHION TECHNOLOGY

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. Dyeing2. 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 GOOD QUALITY

1 . C o n s i s t e n c y

2 . U n i f o r m i t y

3 . K n i t s -   L o w   T e n s i o n

4 . W o v e n   – P e n e t r a t i o n

COMMON CAUSES OF DEFECTS

1. The material is not well prepared for dyeing and printing

a. Material having dead fibres or other defective fibresb. Left over of Chemicals after bleaching etc.c. Material not properly desizedd. Material not properly mercerised.e. Absorbancy of the fabric not properf. Sticking of insoluble material on the fibresg. Impurities are not removed properlyh. Uneven heat treatment. 

2.Water Quality not Proper

a. More Hardness of waterb. Water has metal ions such as iron.c. pH of water not properd. 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 ratio3. Improper filtering of concentrated colors.

4. Due to Shortcomings in the dye machinery

a. Coming out of Dye liquor during dyeingb. Defective instruments controlling temperature, pressure speed etc.

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 O U R   B L E 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.

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.

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 . C R E A S E S T R E A K

-It occurs in tubular knits. It results from creased fabric passing through squeeze rollers in the dyeing process. 8 . D Y E S T R E A K I N P R I N T I N G

-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.

12. TAILING

–Reactive dyed fabrics tend to show Tailing.

13. CSV (CENTER TO SELVEDGE VARIATION)

–As the same suggests it refers to the defect where the dyed fabric colour varies from centre to selvedge. 

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

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   P R 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

S L I 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

D O U B L E   P R 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.

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.

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.

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.

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.

D R O P S

–Stains or unevenness due to drops. Drain (condensed water) or drops are the cause.

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.

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.

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 too low.

ROPE MARK FADING

–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.

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

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, screen mesh and squeegee pressure.

M O I R E

–Moiré patterns appear on printed designs. Screen mesh, the roulettes of routers, the line delineation pattern has to do with this phenomenon.

WATER MARK

–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.

COMMON REMEDIES FOR DYEING AND PRINTING DEFECTS:

NATIONAL INSTITUTE OF FASHION TECHOLOGY

CHENNAI

Department of Fashion Technology

DYEING AND PRINTING

ASSIGNMENT 2

DEFECTS IN DYED AND PRINTED FABRIC

Submitted By-

Rohit Yadav

B/AP/12/247

DFT-III

Submitted to –

Mr. PRAVEEN NAGARAJAN

Assistant Professor

Department of Fashion Technology

CHENNAI

DEPARTMENT OF FASHION TECHNOLOGY

DYEING AND PRINTING DEFECTS

SUBMITTED TO

MR.D PRAVEEN NAGARAJAN

ASSISTANT PROFESSOR

SUBMITTED BY-

RICHA

B/AP/12/1648

DEPARTMENT OF FASHION TECHNOLOGY

SEMESTER- III