Assessment of Fabric Hand (II) Data Analysis on fabric hand value Dr. Jimmy Lam Institute of Textiles & Clothing

Learning Objectives n Subjective Hand Assessments on wool/wool blend fabrics and cotton/cotton blend fabrics. n The relationships between primary hand values and total hand value on hand assessments.

Subjective Assessment of Hand Wool/Wool Blend fabrics n Based on the criteria of hand assessment as discussed in previous section, a total of ten wool/wool blend fabrics are used to conduct the subjective hand assessments in Hong Kong. n The fabric weight ranges from 150 g/m to 242 g/m, with material of pure wool and wool/polyester blend fabrics. n The fabric weight ranges from 150 g/m 2 to 242 g/m 2, with material of pure wool and wool/polyester blend fabrics. n The surveyed fabric samples are shown in Table 2.9 and the average primary hand value and total hand value (THV) of these ten fabrics assessed by the panel of twenty-eight judges are shown in Table 2.10

Research Questions n Table 2.10 shows the survey results from twenty-eight judges on ten wool/wool blend samples on fabric hand assessment. n What can you tell from these Primary Hand Values and Total Hand Value ? n Are there any relationship between Primary Hand Values and Total Hand Value? n If there is, which one plays a significant role to explain the total hand value of these ten fabric samples? n Are there any variations between these twenty-eight judges on fabric hand values assessment? n The results from these survey (expert judges) can it be simulated by a set of testing instruments? If so, objective measurement can be done on fabric hand.

Correlation Matrix (1) Primary Hand Values & Total Hand Value n To access the relationship between the fabric total hand value (THV) and the primary hand values of these ten wool and wool blend fabrics for men’s winter suitings, a correlation analysis was carried out with the results shown in Table 2.11 n The results shown that THV is positively correlated with fabric smoothness with R=0.84, but negatively correlated with fabric stiffness with R= n This means that the primary hand value of smoothness of these ten wool/wool blend fabrics as assessed by the judges make a significant positive contribution to the fabric total hand value.

Correlation Matrix between THV and Primary Hand Values

Correlation Matrix (2) n For the fabric primary hand value of stiffness, the result means that the smaller is the stiffness, the higher is the total hand value as assessed by the judges. n The relationships of THV to fabric smoothness and stiffness is shown in Figure 2.1 and 2.2 respectively. n It should be noted that the primary hand value of softness as assessed by the judges, does not play any significant role in determining the fabric total hand value, with correlation coefficient of R=-0.11.

Summary n In summary, the judges in favour a large fabric primary hand value of smoothness to contribute directly to the fabric total hand value for these ten wool/wool blend winter suiting fabrics. n For the primary hand value of fabric stiffness, the lower is its value, the higher is the total hand value for these ten wool/wool blend fabrics. n This is true as the quality of the high grade wool suitings is normally determined by fabric smoothness and fabric stiffness plays a negative role in determining the fabric quality. n However, it is interesting to note that the judges do not agree on the contribution of the primary hand value of softness to the total hand value of these wool/wool blend fabrics when considered for use as men’s winter suiting materials.

Subjective Assessment of Hand for Cotton/cotton blend fabrics

Hand assessment on Cotton denim fabric n Another set of ten cotton/cotton blend fabrics was selected to conduct the subjective hand assessment. n These ten medium to heavy weight cotton fabrics are mainly used for trousers or denim and the fabric weight ranges from 199 g/m2 to 500 g/m2. n The fabric structure is twill and the fibre composition is pure cotton with some of fabrics using Lycra as a weft yarn to increase the fabric extensibility. n The cotton fabric characteristics are shown in Table The average primary hand values and total hand values of these ten fabrics are shown in Table 2.16.

Research Questions for cotton denim fabrics n Similar to wool/wool bend fabrics, what conclusion can you draw from Table 2.16? n Are there any relationships between primary hand values and total hand value for these ten medium to heavy weight denim fabrics? n If so, which one plays a significant role to explain the fabric total hand value? n What are the difference between the primary hand values and total hand value obtained from these cotton fabric to wool fabrics?

Correlation Matrix for cotton/cotton blend fabrics

Results of cotton fabrics n Table 2.17 shows that the THV has a strong positive correlated with fabric smoothness with R=+0.96, but negatively correlated with fabric stiffness with R= n This means that the twenty-eight judges agree on the fabric smoothness as one of the key positive factors contributing to the total hand value for these ten cotton fabrics for denim trousers. n For the primary hand value of stiffness, the lower is its value, the higher is the total hand value. n This latter result shows that the judges do not favour fabric stiffness from the viewpoint of fabric hand.

Results: Cotton Fabrics (1) n The two results for the primary hand values of fabric smoothness and stiffness contribute to THV for cotton fabric are in the same sense as for wool/wool blend fabrics for men’s winter suitings. n There is a weak positive correlation between THV and primary hand value of softness for these ten cotton/cotton blend fabrics, with correlation coefficient of R= n These judges have difficulty in determining whether the fabric softness contributes to the fabric total hand value. n Although fabric softness shows a weak positive correlation with THV for these cotton fabrics, the judges are not sure if the effect on softness will play a significant part in explaining the fabric total hand value.

Results: Cotton Fabrics (2) n It is interesting to note that the judges maybe in slightly better agreement on fabric softness for these ten cotton/cotton blend fabrics (for denim trousers) than for wool/wool blend winter suiting fabrics. n The correlation coefficient between fabric softness and THV for cotton/cotton blend fabrics is and for wool/wool blend fabrics is only n The judges appear to have more difficulty in determining the effect of fabric softness on THV for wool/wool blend fabrics than for cotton fabrics.

Discussion n What conclusion you can draw from the hand assessment between wool and cotton fabrics in this study? n What are the relationships between primary hand values and total hand value on these survey? n Is it possible to draw a generalization on fabric hand value on wool and cotton fabric? n Is it possible to simulate the knowledge of expert judgements on a simple set of testing instruments ?