What is tartan

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What is tartan

  1. 1. What is Tartan?Tartan can initially appear complex in design but is based on a simple concept - a pattern ofstripes which repeats in both a horizontal and verticle direction - in weaving terms the warp andthe weft. A sequence of stripes (the sett) starting at one edge is repeated but in reverse orderround a pivot point. The sett reverses again and repeats round a second pivot point - see diagramA. This process continues for the width of the material in question. The same sett and mirroringsequence occurs in the weft - diagram B - continuing for the entire length of the material. Theresulting combination of warp and weft is the tartan - diagram C. (Note that the pivotsthemselves are not doubled in the mirroring process).Illustrations by Don Pottinger{gallery}large_images{/gallery}Click on this image for an enlarged viewSome tartans - known as asymetrical or non mirrored do not reverse the sequence at the pivotpoints but simply repeat the sett in the same sequence. A very small number of tartans havedifferent thread counts for the warp and the weft.A description of a tartan can be written in a format known as the thread count or the sett. Thisidentifies the colour and width of the stripes between two pivot points and incorporates the sameinformation for the pivot points themselves. It takes the form of e.g. B16, LG8, K4, G24, K6 -reading the sequence from the left. The outside threads (B16 and K6 in the example given) arethe pivot points. The colour is determined by a one to three letter shorthand - K for example isblack, B is blue, LG is light green and so on. The number after the letter is the proportionalmeasurement - it does not matter what unit of measurement is used as the actual tartan patternwill remain the same - reflecting the abstract nature of tartan design. Traditionally the numberrefers to the number of threads used to set the loom but this can of course vary depending on thetype and weight of thread used - modern tartan fabric can be made from silk, wool, cotton, poly-viscose, etc. In addition tartan designs are now used extensively on non-woven materials - paper,plastics, packaging, wall coverings, etc. although some claim that a tartan needs to be wovenbefore it can be considered a true tartan.
  2. 2. UNIT ⅡCompound StructureIntroduction:Fundamental and combined weaves are considered to be simple, though there is a great variety oftypes and constructions. In these weaves, only one system of warp threads is interlaced with onesystem of weft threads at right angles. Due to this, the methods of construction of these weavesand production of fabrics of such weaves at textile mills are rather simple.Compound weave fabrics are of a specific structure, therefore special methods andmechanisms should be used in their production.Chapter SixBacked weavesThe principle of backing a cloth with a second series of either weft or warp threads is to addextra weight and warmth without interfering with the smooth surface of the fabric. The end usesof backed cloths range from apparel to furnishing.6.1 Backed warp weaves1. Concept:
  3. 3. These are weaves which have two systems of warp and one system of weft. The face weave isformed by interlacing face warp and weft. The back weave is formed by interlacing back warpand weft.2. Construction of warp backed weaves:(1) Selection of face weave and back weave:The face weave can be same as the back weave, and can be differ from the back weave, butthe face weave should be warp-faced weave such as 3/1 twill, back weave should be weft-facedweave such as 1/3 twill.(2) Selection of the starting point in construction of a back weave:In order to get a better appearance of the fabric, the backing stitches (back warp floats) shouldbe hidden between floats on the face. So the warp floats of the back weave should be in themiddle of the adjacent warp floats of the face weave. The setting of the face warp should bedense enough to prevent the binding marks of the back warp showing through.(3) Determine the arrangement of the face and back warp:The threads of the back warp can be arranged either alternately or in the proportion of twoface threads to one back thread, i.e, m:n = 1:1 or m:n = 2:1.(4) Calculate the “new repeat”Ro= )Ry=Here: LCM—Least common multiple.Ro—The warp repeat of the backed weave.Ry—The weft repeat of the backed weave.Rm—Face weave warp repeat.Rn—Back weave warp repeat.m, n—The warp arrangement of face weave and back weave.(5) transferring the weave:
  4. 4. E.g. A backed weave:Face weave : ↗Back weave : ↗Warp ration: 1:1Ro == 4×2 = 8Ry = = 4Construction of an backed warp weave diagram.(1) Select : the face weave 3/1 Z twill,the back weave 1/3 Z twill. See Fig. 6.1.(A), (B). Arrangement 1:1.(2) Determine the starting point which must meet the previous point (2), i.e. stitching floatshould be covered by the face warp float. See Fig. 6.1 (C)The Arabic numbers indicate the face warp ends.The Roman numbers indicate the back warp ends.The dots indicate the back warp threads over the weft threads.(3) Calculate the repeat and outline the repeat.Here: Ro = 8 Ry = 4. See Fig. 6.1 (D)(4) Transferring the weavesSee Fig. 6.1 (E).
  5. 5. (A) (B) (C) (D)(E)(E)Fig. 6.1 Construction of backed warp weave6.2 Backed weft weaves1. Concept:These are weaves which have two systems of weft and one system of warp. The face weave isformed by interlacing warp and back weft. The back weave is formed by interlacing warp andback weft.2. Construction of backed weft weaves:The principles of the construction of backed weft weaves are similar to backed warp weaves.(1) Selection of face weave and back weave
  6. 6. The face weave can be same as back weave, and can differ from the back weave, but the faceweave should be weft-faced weave such as 1/3 twill, back weave should be warp-faced weavesuch as 3/1 twill.(2) Determine the stitching distributionThe correct stitching plays a very important part in the construction. On no account must it bevisible on the face of the fabric.The density of the fabric also plays an important part in achieving perfect stitching.(3) Determine the arrangement of the face and back weft. The threads of the back weft can bearranged either alternately or in the proportion of two face threads to one back thread, i.e., m:n=1:1 or m:n = 2:1.(4) Calculate the new repeatThe calculation of the new repeat is similar to backed warp weaves. The difference isreplacing the warp by weft.Construction of an backed weft weave diagram is similar to backed warp weaves. We learntpreviously. Same example are shown bellow:
  7. 7. Example 1: See Fig. 6.2.Cross-section:Face weave = pick 1Back weave = pick 2Arrows = stitches.Development of structure.Face weave: 1/3 Z twillBack weave: 3/1 Z twillStitching is marked with circles (lowering of ends).Horizontal lines between face picks represent back picks 2,4, 6, 8. The back picks are stitched between weft floats ofthe face picks.The stitching should be distributed in rotation over everyend to avoid different tension on individual ends.The correct stitching plays a very important part in theconstruction. On no account must it be visible on the face ofthe fabric.Transferring the weaves.Warp: solid Weft: 1 face-1 back.Repeat: 4 ends/8 picks.Face weave on odd picks,Back weave with stitching on even picks.Lifters/: ends over back picks,Circles are cancelled lifters (lowering of ends).
  8. 8. Reversible weave: identical interlacing on both sides of the fabric.Completed structure with draft and lifting plan.These symbols represent warp up.Fig. 6.2Construction of weft backed weave.
  9. 9. Example 2:Weft BackedIn very dense warp setts the stitching points of the backing weft may be extended over two or more repeats ofthe face weave.Cross-section:Face weave = pick 1Back weave = pick 2Arrows = stitchesFace weave: 2/2 Z twill, repeated twiceBack weave: 7/1 satinRepeat: 8 ends/16 picksWarp: solidWeft: 1 face-1 back pick
  10. 10. Cross-section:Face weave = Pick 1Back weave = pick 2Arrows = stitchesFace weave: 2/2/1/3 Z twillBack weave: 7/1 Z twillRepeat: 8 ends/16 pickswarp: solidWeft: 1 face-1 back pick
  11. 11. Fig. 6.3 Construction of weft backed weaveExample 3: see Fig. 6.4Weft BackedExamples of reversible weaves. The heavier yarn count in weft covers the finer warp on both sides of thefabric entirely. These fabrics generally receive a milling and raising finish.Cross-section:Face weave = pick 1Back weave = pick 2Arrows =stitches.Face weave: 1/4 sateenBack weave: 4/1 satinRepeat: 5 ends/10 picksWarp: solidWeft: 1 face-1 back pick
  12. 12. Cross-section:Face weave = pick 1Back weave = pick 2Arrows = stitchesFace weave: 1/7 sateenBack weave: 7/1 satinRepeat: 8 ends/16 picksWarp: solidWeft: 1 face-1 back pickIdentical interlacing on both sides of the fabrics.Fig. 6.4Construction of backed weft weaves
  13. 13. Example 4: see Fig. 6.5Weft BackedDevelopment of patterns with two effects. The cross-section shows theinterchanging of face and back picks.Effect IFace weave: 1/3 broken twill (pick 1,3, 5, 7)Back weave: 3/1 broken twill (pick 2, 4, 6, 8)Effect IIFace weave: 1/3 broken twill (pick 2, 4, 6, 8)Back weave: 3/1 broken twill (pick 1,3, 5, 7)Check-pattern.MotifTo enlarge the design each section of the structure can be repeated toachieve the required size.Repeat of one section: 4 ends/8 picksWarp: solidWeft: 1 face-1 back pickThis example can be woven with 8 shafts.
  14. 14. When developing patterns, it is important to plan the weaves to cut with each other at the point of interchangebetween face and back. This assures clarity of design.Motifs.Each square represents 4 ends/8 picks.Each symbol of the condensed draft above the motif represents one group of four shafts.These examples can be woven with 16 shafts.These motifs can be developed with the same weaves as above.Fig. 6.5Construction of patterns of backed weaves
  15. 15. 3. Fabrics setting:The proper set and yarn linear density are also important in achieving perfect appearance.The warp density should be considerable lower, and the weft density should be higher due tothe fabric effect depending the weft.The count for the backing pick can be softer in twist, but should not be heavier than the faceyarn, especially on a 1 face-1 back ratio.The warp yarn should be stronger considerably due to its bearing the beating force duringweaving process.Homework:1. Construct backed warp weaves:(1) Face weave 3/1↗, back weave 1/3↗, arrangement of face warp and back warp m:n=1:1(2) face weave 8/5 satin, back weave 1/3↗, m:n=1:1.2. Construct backed weft weaves and their cross-section diagram.(1) face weave 1/3 broken twill, back weave 3/1 broken twill, m:n=1:1.(2) face weave 2/2↗, back weave 3/1↗, m:n=1:1.

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