Assessment of Fabric Hand

1. Assessment of Fabric Hand Dr. Jimmy Lam Institute of Textiles & Clothing

2. Learning Objectives • What is fabric hand and how to make assessment of fabric hand? • FOUR conditions to access fabric hand, they are: 1) the judge; 2) judgement criteria; 3) assessment conditions and 4) ranking method

3. Introduction • One of the important attributes used in the textile and apparel supply chain is fabric handle. • Evaluation of fabric quality has traditionally been assessed subjectively in both textile and clothing industries. • The simplest and most widely used method of subjectively assessing fabric quality is through the notion of fabric handle.

4. Subjective Assessment • How reliable is this kind of judgement? • Can they reproduce the same results? • How they made this judgement (says good, average or bad)? • Can we reproduce the same results by a machine (objective judgement) ?

5. Fabric Hand - Definition • The term hand has been defined as “the subjective assessment of a textile material obtained by the sense of touch. • Hand is thus a physiological and psychological phenomenon. • It implies the ability of the fingers to make a sensitive and discriminating assessment and of the mind to integrate and express the results in a single valued judgement. • Such a judgement cannot be obtained objectively, since the relevant mechanism of the sensory organs, the nervous systems, and the brain are not known and vary from individual and also with time for each individual.

6. Fabric Handle • Fabric handle is, therefore, not really a property in itself; rather it is a very complex compilation of all fabric properties which can be assessed by human touch. • Fabric may be assessed as having superior handle for a variety of reasons. • For example, the fabric may have good tailoring properties, comfort, various aesthetic qualities and drape.

7. Subjective assessment of fabric hand

8. Four Conditions • Four steps involved in the subjective hand evaluation with particular reference to use of the results in Fabric Objective Measurement (FOM) systems are: • The judges, in particular their expertise and cultural background • The criteria of judgement, the choice of descriptors for fabric attributes • The assessment conditions, fabric seen or unseen, controlled temperature and relative humidity • The method of ranking or scaling the assessment.

9. Condition#1 Judgement • Who makes better judgement? Someone with ten years experiences working in textile industry or a fresh graduate from university. • In order word, can an expert make better judgement than non-expert ?

10. Binns Experiment • In the earliest work on subjective hand evaluations, Binns (1926, 1934) investigated the effect of judges’ technical and sociological backgrounds on the ranking in various fabric samples. • In one study, Binns (1934) used two panels of judges comprising: • 22 experienced manufacturers and buyers of fabric similar to those used in the tests; • Six teenage boys of mixed abilities

11. Binns Experiment Results

12. Results • These judges were asked to rank two groups of fabrics in order ranging from “best” to “worst” hand, without any instruction on what fabric attributes to look for. • These two groups of fabrics each consisted of the same six fabrics, but one group had a “clear” finish whereas the other group had been milled. • The Sperman rank correlation coefficient between expert and boys’ ranking is 0.73 for the milled finish and is 0.95 for the clear fabric. • Binns concluded that “ while the tactual or handle judgement appears to be native and immediate, it does not imply that any person is qualified to buy or sell textiles, there are many other factors to be considered.”

13. What weave makes the strongest fabric?

14. Condition#2 Criteria of Judgement • Having decided who makes the judgement (expert in textile area or non-expert), what are the criteria of judgment? • Is it good enough to say, the fabric is “GOOD” or “BAD”. • If not, what else we should look for ?

15. Fabric Descriptors • Howorth and Oliver used a panel of 25 laboratory assistants with no special experience in handling fabrics, to rank 27 samples of worsted suiting fabrics. • All descriptive terms and their frequency of use were shown in Table 2.2. • It was found that 86% of all decisions were made on the basis of the nine most frequency used descriptors. • David used “bipolar descriptors” to qualify the fabric as shown in Table 2.3

16. Criteria of Judgment Covered 86%

18. HESC Standard • Kawabata and Niwa (1989) generated fabric descriptors through discussion with a panel of expert judges in Japan, the Hand Evaluation and Standardization Committee (HESC) in the context of specific fabric end uses. • Kawabata reported that initially the expert did not recognize that they evaluated fabric quality (total hand value) on the basis of a number of specified properties. • However, when the experts were questioned as to the reasons for selecting one fabric rather than another, the Japanese judges always replied on fabric attributes in terms of smoothness, stiffness and crispness. • Kawabata called these descriptors “Primary hand value”. • Figure 4.1 shows the Primary Hand Value and Total Hand Value defined by Kawabata

20. Condition#3 Evaluation Conditions • The term “hand” defined by the Textile Institute as “the subjective assessment of a textile material obtained from the sense of touch” is somewhat vague to allow its evaluation in either “seen” or “unseen” conditions. • The systematic evaluation of handle, based on a definition that is specific to the sense of touch, might be expected to involve taking precautions to exclude bias caused by fabric appearance and possibly even by fabric odour and also any rustling sound made by some fabrics.

21. Evaluation Conditions • Should fabric be assessed by “touch” only or “sight-and-touch” together? • The work of Hallos (1990) concluded that “sight-and-touch” approach was of a higher order than tactile perception. • It therefore, might be expected that visual perception only, and visual and tactile perception together, should afford greater discrimination between fabrics than touch alone.

22. Condition #4Ranking fabric attribute • How do we rank the fabrics? (Good or bad) • If we want to compare one sample with others, the ranking must be scaled to certain standard.

23. Ranking samples • Subjective assessment of fabric properties that are intended for correlation with objective measurements must be scaled in some way. • The work developed by Kawabata (1982, 1989), in celebration with Japanese HESC, provided a set of commercially available primary hand standards, representing a full range of quality attributes for this scaling purpose.

24. Ranking of Primary Hand and Total Hand Value

25. Summary (1) • Assessment of Fabric Hand is complex process. • The definition of fabric hand and evaluation process are not yet defined properly. • Four criteria are needed to access fabric hand properly, they are 1) the judges; 2) judgement criteria; 3) assessment condition and 4) ranking method.

26. Summary (2) • It was found expert judges and non-expert judges cannot distinguish textile fabric completely based on fabric hand alone. • However, results from expert judges make less variation (or degree of fluctuation) than non-expert judges. • The judgement criteria are normally based on Kawabata Primary Hand and Total Hand Value • The assessment conditions are normally based on “Sight-and-touch” as they are most commonly used in the industry. • The ranking method is normally based on HESC as a standard is established for comparison directly