Dyeing And Printing Flashcards
Describe the process of continuous dyeing
The whole fabric is placed under a small pad bath with the dye and is gently squeezed to ensure the colour spreads evenly.
Name 3 methods of industrial dye processes
Continuous (pad) dyeing, semi-continuous dyeing and batch dyeing.
Describe the process of semi-continuous dyeing
The fabric is dyed then wound up on a batching roller to remove excess dye, allowing it to fix into the fabric.
Explain batch dyeing
The fabric is placed in a dye bath where the fabric absorbs colour but it must be exact in order to create an even colour.
Name 3 systems used in batch dyeing
Jigger system, winch system and jet-dyeing process
Which direction does each of jigger, winch and jet-dyeing go in?
Jigger goes forward and back through a bath. Winch goes in circular movements. Jet moves the machine not the fabric to spread the dye evenly.
Which fabrics does jigger work best with?
Medium woven fabrics such as tweed
What fabrics work best with the winch system?
Knitted fabrics and lightweight woven such as silk
How can dyeing and printing affect the environment?
Causes water and air pollution. There are now laws passed controlling wastage, chemicals and emissions.
What are super critical fluids?
Recent developments to control wastage of gases - turns into liquid carbon dioxide.
How can the environment affect dyes?
Thermo-chromatic dyes change colour when exposed to heat or sunlight.
Name 4 methods of dyeing
Industrial, chemical, natural and resist.
What does dyeing involve?
Additives (salt) and water to fix the dyes and stop them from running - a mordant.
What is printing?
The application of colour to a fabric in a uniform ‘patterned’ way.
What fabrics are most suitable for printing?
Smooth and tightly woven fabrics will hold colour (fastness)
Name 5 types of dye
Reactive, vat, naphthol, disperse and cationic
What dyes work best for cotton, wool and polyester?
Reactive dyes work best for cotton. Acid dyes or chrome works best for wool and disperse and cationic dyes are most suited for synthetics.
Name 3 printing techniques
Direct, discharge and resist
Describe direct printing
Printing directly onto a white or plain coloured fabric. The imprinted dye will be made from paste, water and a thickening agent such as alignates/gums (seaweed).
Why is alignate more suitable than corn starch as a thickening paste?
It is easier to wash out, it does not absorb the colour and allows better penetration of colour.
Explain the process of discharge dyeing
Fabric is dyed then the colour is removed using chemicals such as bleach which destroys the colour. It is then steamed and washed.
Describe resist printing
A resist paste is imprinted onto the fabric then dyed which leaves behind a pattern once the paste is removed.
Give two example of resist dyeing
Batik and tie dye
Describe the process of batik
Wax is used as a resist which does not accept dye leaving behind an uncoloured pattern. However wax will affect the properties of a fabric.
Give 10 example of direct printing
Block, roller, stencil, screen, transfer, digital, sublimation, electrostatic, photo and air brush/jet spray
Describe the process of sublimation printing
Large inkjet printers with specially formulated inks print the reverse pattern onto heat proof transfer paper. The pigments are suspended in a solvent before the design is transferred using heat up to 210 degrees. The dye turns into a gas an penetrates the fabric before solidifying.
Give 4 advantages of sublimation printing.
It is permanent - does not fade or peel. Fabrics can be washed without damaging the pattern. Colours are brilliant and clear with continuous tones. The print covers all parts of the fabric.
Give 3 disadvantages of sublimation printing.
Can only use synthetics such as polyester. The printer speed is very slow can be expensive. Creases leave dye marks.
How does transfer printing differ from sublimation printing?
The process of vaporisation is used using either wet or dry heat. Electrically heated cylinders and heat resistant blankets absorb the dye leaving behind the pattern.
Give 2 disadvantages of transfer printing.
It can be costly. It is a lengthy process as it requires a lot of pre-process treatment/opponents.
Which fabrics does jigger work best with?
Medium woven fabrics such as tweed
