Wk 8 Adding Colour Study Notes PDF

Wk 8 Adding Colour Study Notes: Why is colour an important element in textile development? sell’s a poorly made product is the cause of an emotional purchase can make a not wanted fabric more marketable Reactive Dyes good colourfastness properties no heavy meta...

Wk 8 Adding Colour Study Notes: Why is colour an important element in textile development? sell’s a poorly made product is the cause of an emotional purchase can make a not wanted fabric more marketable Reactive Dyes good colourfastness properties no heavy metals (Colourfastness = the bond between the dye, the yarn and the fabric) Disperse Dyes used for dying synthetic fibers like polyester, nylon, acrylic, and acetate rayon Least sustainable of the dyes Good colourfastness Natural Dyes Some metallic salts used to make yarn or fabric for dyeing are toxic for the ecosystem Potassium aluminum sulfate is the most common mordant for both animal and plant fibers Un-dyed Naturally coloured cottons, brown, rust, and green, are more drought and pest- resistant Easier to grow organically Sustainable option: Using flower petals to dye fabric Dyeing and printing 2 most common methods of applying colour to fabric Method 1, Dyeing – Applying Colour  Stock Dyeing o Staple fibers are dyed before they are spun into yarn o Usually wool o Benefits: saturates colour - colour is more colourfast - won’t fade with washing o dying wool will than be spun into yarn for weaving and knitting o No 2 dye lots can be exactly the same colour Yarn Dyeing o Synthetic fibres ▪ colourant is added to the yarn while it is being made ▪ Synthetic yarn can be extruded as a coloured yarn so the colour is a part of the yarn ▪ Synthetic yarns are best for not washing out or dying other fabrics when in the washing machine o Natural dyes ▪ Usually used for hand knit sweaters ▪ Many of these dyes are made with natural ingredients like nuts, indigo, leaves, beans, insects ▪ Colourfastness is poor Piece Dyeing o Adding colour to undyed woven or knit fabric = Piece Dyeing o fabric is one long piece o not as perfect as with yarn dye o 1 solid colour Garment Dyeing o Already sewn greige garments are dyed in a large washing machines o Industrial dye machines handle both greige (undyed) fabric and finished garments Yarn dyed woven fabric o Has a distinct warp and weft (horizontal/vertical) layout Spaced dyed yarn o dyed in consistent lengths of repeating colours o Missoni uses a lot of space-dye o Less expensive than stock dyeing but its more expensive than piece dyeing Yarn dye in knit o Fleece is often yarn dyed because consumers like the marled yarn look in fleece Printing Screen printing o Oldest form of printing o Only used in fashion o Screens were originally made of silk 4 Types o Hand Screened o Automatic Screen Printing o Rotary Screen Printing o Laser Printing Automatic screen-Printing machine o 8 colour screen separations available o Used on garments or panels of unsown garments o Size limitations Automatic Silk Screen Printing o Each screen is cut for only 1 colour o 8-panel screen machine can deal with up to 8 colours in the final picture o The t-shirt (most common use of this method) is placed on the board below the screen o The dye on each colour must dry before another colour can be added Hand Silk Screen Printed Fabric o Premise is the same, instead the screen is moved along the length of the fabric o Aligning the screen is important Heat Transfer Printing o Patterns are first printed onto sublimation paper o Hand of fabric is not affected o More expensive printing method Ink Jet/Digital Printing o Started in the 1980s as a possible replacement for analog screen printing o Sometimes referred to as Digital Ink Jet Printing o 4 colours create a multi coloured print Digital textile printing o Patterns made and stored in a computer can be selected, scaled, and printed right onto the fabric  o very small drops of dye are added to the fabric through inkjet print heads, a lot like printing paper o The quality of the print depends on colour registration, matching accuracy, colour overlay, and the hand feel and colorfastness Fabric Finishes Finishing is the final treatment of fabrics, to enhance performance Finishes can be grouped together as either chemical treatments (applied at the last stage of fabric production) or mechanical finishes Chemical Finishes o A chemical finish can include bleaching or mercerization (applied to cotton at the yarn or fabric stage), which enhances luster and strength o Other common Chemical finishes include: ▪ Sanforizing – used to reduce shrinkage in final garment ▪ Scotchguard – stain resistant finish for upholstery, suitings, coats, sometimes ties ▪ Zepel – is a brand of water repellent finish used for raincoats ▪ Antistatic – chemical application that prevents clinging ▪ Calendering – an ironing process with starch and water to produce a smoother, stiffer, polished fabric ▪ Permanent Press – applied heat, resins or liquid ammonia to permanently hold a crease ▪ Flame Retardency – chemical treatment to make fabrics resistant to burning ▪ All of these are clear Mechanical Finishes o machinery to alter fabric texture. For example, brushing with steel brushes creates a nap o Flocking – creating a 30 dimensional design with engraved rollers ▪ creating a 3 - dimensional design with engraved rollers o Napping – brushing the surface of the fabric to raise the small fibers for a pile effect ▪ brushing the surface of the fabric to raise the surface. Velveteen and Corduroy are examples o Moireing – achieving a watermarked effect by using etched rollers ▪ achieving a watermarked effect by using etched rollers that press a pattern using heat, into the fabric o Plisseing – adding a crinkled effect by pasting sodium hydroxide onto fabric, resulting in shrinkage and thus a crinkled look ▪ adding a crinkled effect by pasting sodium hydroxide onto fabric, resulting in shrinkage and thus a crinkled look o Singeing – smoothing a fabrics’ surface by passing it over a gas flame to burn off tiny fibers o Pleating – using heat (sometimes resins) to create a permanent pleated pattern in fabric ▪ using heat and pressure (sometimes resins) to create a permanent pleated pattern in fabric. This only works well on synthetic fabrics o Quilting – patterns are stitched over layers of fabric to create warmth or 3D texture ▪ Sewing together layers of fabric either for warmth or fashion