Unit 1: Fabric Colouration and Decoration Flashcards
Unit 1 - Design
1
Q
Applying Colour - printing and dyeing
A
- Fabric can be coloured by printing or dyeing methods
- Dye: from plant and animal substances. Eg. Indigo: from the leaf Indigofera tintorial, Tyrian purple: derived from shellfish.
- Contemporary Textiles Industry: aware of consumer desires for ‘just the right colour’
- Manufacturer’s: aware of this as well, and how consumers are irritated when colour is not maintained for the anticipated life span of the garment (colour fastness).
2
Q
Work health and Safety - printing and dyeing
A
- Dyestuff and printing pastes must be handled, stored and used following the maker’s instructions in order to maintain a safe working practice when dying and printing..
- Instructions may include: always wear rubber gloves and protective covering e.g apron, Do not consume food in the work area, work in a well ventilated area.
3
Q
Printing
A
- A pigment is an insoluble, coloured substance that is applied to the surface of the matter being coloured, usually attached with a binding material.
- Printing is a surface decoration that allows flexibility in colouration of patterned fabrics.
- Printing designs on fabric is the economically efficient way to colour or pattern fabric.
- Printing is a cultural and contemporary textile colouration form for yarns and fabric.
4
Q
The Principles of Printing
A
- A printing bed is prepared using a soft resist under a hard surface.
- Viscous printing paste is applied to the raised surface of a print tool.
- The print tool is pressed firmly into the fabric (sometimes a rubber mallet is used to ensure even contact).
- Often the printed design is repeated, where aligning the print is known as ‘registration’.
- Printed fabric is then fixed using heat, either ironed or steamed, to ensure the print paste penetrates the fibres.
- Printed fabrics are washed to remove any excess print paste, debris or residue/non-fixed colour.
5
Q
Direct printing
A
- Most common printing technique.
- Design is directly printed onto the surface of the fabric.
- Direct printing includes: block printing, roller printing and warp printing.
6
Q
Block printing
A
- One of the oldest methods of printing.
- Blocks are made using potatoes, wood, foam, metal or lino, where a design is carved.
- These designs are usually hand-carved and are unique, though due to this process, block printing tends to be slow and time-consuming.
- This is because it’s often found difficult to align design work when repeating patterns.
7
Q
Roller printing
A
- Roller printing allows multi-colour printing,
- It is a cheaper method of printing than block as it’s less labour-intensive.
- Roller printing is a continuous mechanical process that can produce large quantities of fabric.
- The roller itself is engraved or etched with a design that is rolled onto fabric to repeat that pattern.
- Each roller usually holds a different colour to print intricate designs with complex detail.
- Excess print paste is scraped from the roller by a small blade to ensure a sharp print.
- The role of the blanket is to absorb any excess colour.
8
Q
Warp Printing
A
- Used to design onto warped yarns, often then woven with plain-dyed weft yarns.
- The printed yarn produces a fabric with soft, blurry, muted-tones designs (often used for taffeta and furnishing fabrics.
9
Q
Resist Printing
A
- Used to prevent the printing paste being applied and absorbed into the fabric.
- Methods include: Batik, stencil printing, screen printing and Ikat.
10
Q
Batik
A
- Wax is stamped using a tjap or drawn onto the fabric using a tjanting.
- Then it is later dyed, where the process of applying wax stops the dye from absorbing into the fabric, creating intricate designs.
- This process can be repeated on the same fabric to create different effects and colours.
- After dyeing is complete the wax is scoured off from the fabric.
- It is slow and laborious as it is a manual process that requires careful planning to achieve the desired results.
11
Q
Stencil printing
A
- Uses such as acetate, plastic, contact paper or masking tape.
- A design is cut into sticky resist film or paper and then applied to the fabric, then brushes or sponges are used to apply the printing paste and colour the design.
12
Q
Hand or Manual Screen Printing
A
- Developed from stencil printing, screen printing is the process were screens are made for each colour to be used in a design so that an overall design or pattern can emerge.
- A frame is laid into the printing bed and a squeegee is used to force printing paste through the designed areas on the screen mesh. Then it is carefully lifted from the fabric and is repositioned for the next print.
- Hand: involves labour-intensive work and excellent skills in registration, where different colours are involved in design work.
13
Q
Direct Digital Printing
A
- Or DDP, involves printing directly onto fabric using inkjet technology and innovative CAD systems and programs.
- Reactive dyes are used to print onto natural fibres such as cotton, silk, rayon and viscose.
- Disperse dyes are used to print onto polyester.
- DDP requires high-end, large-scale specialist print machines capable of printing directly onto widths of fabric. Where the design is limited to the size of the printer used.
14
Q
Dyeing
A
- A dye is a soluble colour that is applied from a solution called the dye liquor 9dye solution).
- It penetrates and combines with the fibre, yarn or fabric.
- Types of dyes: Direct - cellulosic. Reactive - cellulosic, wool, silk, acrylic and nylon. Sulfur - cellulosic. Azoic - cotton and some polyesters. Vat - cellulosic. Acid - wool, silk, nylon, modified rayon, acrylic, and polyesters. Basic - acrylic, polyester. Nylon, and discharge prints on cotton. Disperse - polyester, nylon and synthetic fibres. Natural - Primarily natural fibres.
15
Q
The Principles of Dyeing
A
- The quality of dye is made by dissolving the dyestuff in water, determined by the weight of the fabric dyed. This is known as the dye solution/dye liquor.
- The fibre, yarn or fabric is traditionally wetted out to assist the fibers to swell, causing polymers to move apart slightly making it easier for dye to enter. The swelling makes the uptake of dye slower yet easier, and enhances the consistency of the colour.
- The fibre, yarn or fabric is immersed in a vessel full of dye solution/liquor, called a dye bath or vat. The solution/liquor can be applied as an emulsion or foam.
- The dye solution/liquor is agitated to assist dye intake.
- The dye solution/liquor then goes through MIGRATION, where the dye molecules are attracted and move towards the textile fibre, yarn or fabric (EXHAUSTION).
- Dye molecules then undergo DIFFUSION, where they move or diffuse into the amorphous regions of the textile, and may be fixed in a variety of ways, ANCHORING the dye molecules into the fibres.
