TAM 2200 Notes Ch. 19 - Kerri McBee-Black PDF

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Kerri McBee-Black...

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Ch. 19: Dyeing and Printing Intro ● Color is one of most significant factors in appeal and marketability of textile products ● Manner in which color is added and chemical nature of colorant impacts product appearance, performance, rate of response to fashion change, quality and cost ● Colorant is general term describing materials that are used to add color to fabric ● Either dyes or pigments ● Colorfastness refers to dyes and prints that do not shift hue or fade when exposed to light or other environmental factors and that do not move onto other fabrics during storage, processing, use or care Color Theory and Practice ● Color theory is complex phenomenon that combines the physics of light, chemistry of colored objects, biology of eye, behavioral sciences and aesthetics ● Work to determine what is seen and how it is perceived ● Color measurement is process of assigning numerical values to color; used to match color and sort shades ● Lab dip is sample that dyehouse sends for color match by creative team Colorant ● Pigments are insoluble color particles that are held on surface of fabric by binding agent ○ Application quick and simple ○ Any color can be used on any fiber ○ Stiffening, crocking and fading can occur ○ More than 80% of printed fabrics are colored ○ Poor colorfastness ○ Easier to match colors w/ pigments than w/ dyes ○ Has fewer sustainability issues compared w/ dyes ○ Poor color strength so more pigment needed to color compared to dyes ○ Pigments sit on surface of textile so this makes pigment dyes more susceptible to abrasion ● Dye is complex organic compound that is used to add color to materials by binding w/ them ● Dye is composed of chromophore, the colored portion of dye molecule, and an auxochrome, which slightly alters color

● Auxochrome makes dye soluble and is site for bonding to fiber ● Dyes are molecules that are dissolved in water to allow them to penetrate fiber ● Dyes have high color strength, more than pigment ● Fabrics printed w/ dyes can be distinguished from fabrics printed w/ pigments b/c dyes penetrate t/o, so color is seen on reverse of fabric ● Dyes can be used in either solutions or paste ● Dye pastes are used for printing ● Complete range of shades is NOT available in each dye class ● Use lot of water and chemicals to control the process Stages of Dyeing ● Color may be added to textiles during the ○ Fiber, yarn, fabric or product stage ● Earlier color is added the less critical the uniformity of dyeing ● Fiber Stage ○ Color is added to fibers b/f yarn spinning ○ Fiber-dyed items have slightly irregular, heather, or tone-on-tone gray ○ Excellent colorfastness ○ Expensive and high quality ● Yarn Stage ○ Can be done w/ yarn in skeins, wrapped on cones, or w/ yarn wound on warp beams and designs more limited ○ More expensive due to larger inventories ○ Better-quality fabrics created w/ yarn dyed yarns ○ Usually produced in stripes or plaids and not solid colors ● Piece or Fabric Stage ○ Bolt or roll of fabric that is dyed ○ Usually produces solid-color fabrics ○ Costs less to dye fabric than to dye loose fibers or yarns ○ Quickest response to fashion change ● Product Stage ○ After fabric is cut and sewn it can be dyed (product or garment) ○ Emphasis is on quick response to consumer; least expensive ○ Distressed looks can be achieved ○ Properly prepared greige goods is critical at this stage for uniformity Methods of Dyeing ● Batch Dyeing is known as exhaust dyeing; textile is circulated through dye bath

○ Can be used at any stage ○ Good flexibility of color selection and low cost ● Package Dyeing dye bath is circulated around textile ○ Used for bulky yarns such as acrylic and wool ● Combination Dyeing both textile and dye bath are circulated Resist Dyeing ● Methods block color absorption during yarn or fabric dyeing ● Treated to block dye absorption in some areas while allowing absorption in other areas ● Batik: generally hand process in which hot wax is applied to fabric in design; wax is hardened and fabric is piece-dyed to add color (#177) ● Tie-Dye: also hand process where areas of yarn or fabric are wrapped w/ thread or string and dye is added; area that was wrapped doesn’t absorb the dye while other area does (#178) ● Ikat: ancient form of resist dyeing; yarn is tied, dyed and then woven; can be applied to warp yarns only or filling yarns only or both (#179) Printing ● Used to add color in localized areas only ● Printed fabrics have sharp edges in design, w/ color rarely penetrating completely into back of fabric ● Allows for greater design flexibility and inexpensive patterned fabric ● Colorways describes different color options available in fabric ● Direct Printing: color is applied directly to fabric in pattern and location desired in finished fabric ● Block Printing: hand process where carved block is dipped in a shallow pan of dye paste and stamped on fabric ○ Expensive and slow ● Direct-Roller Printing: fabric is drawn around metal or foam cylinders during printing; paste b/t rollers and each roller is used for different color (#58, 180, 181, 182); replaced by screen printing ● Discharge Printing: piece dyed fabrics where design is made by removing color from select areas ○ Usually done on dark backgrounds ● Screen Printing: screens etched w/ design; control location of color; one screen/color ○ Flat screen- slower, shorter yardages ○ Rotary screen- cylinder screen, faster, most common method to print yardage ● Digital (ink-jet) printing: computer controlled; ink used

○ Operate with 4, 8 or more basic colors ○ Slower production speed, but getting faster ○ Limits fabric hand and fastness, but can be applied to wide range of fabric and great reproduction of images ○ Used to create smart fabrics; nanoparticles w/ conductive properties are printed on to fabrics Color Problems ● Colorfastness refers to resistance to change in any color characteristic or to transferring color to another object ● Factors that influence colorfastness are: ○ Chemical nature of fibers ○ Chemical nature of dyes and pigments ○ Penetration of dyes into fabric ○ Fixation of dyes or pigment on or in fibers ● Bleeding is loss of color in water or other solutions; may color other fabrics ● Crocking is color transfer to another fabric from rubbing together ● Migration is color movement to adjacent areas of fabrics ● Fading is color loss due to reaction of dye and fiber; caused by heat, light atmospheric contamination ● Frosting occurs when colored portion of fibers or yarns are abraded ● Out-of-register: occurs when 2 colors of print overlap each other and do not meet ● Off-grain prints: fabric is printed off grain and print is therefore off grain Environmental Impact ● Water contamination: chemicals w/ color, salt and heavy metals ● Alternatives to colored textiles: naturally colored fibers or use of natural dyes ● Tech. advancement to improve...