# Advancing Sustainable Textile Metrology: Reflectivity Measurement with Controlled Light Sources
## 3 Results and Discussion  
### Reflectance Ratio  
Figure 5 shows the reflectance ratio of the six knitted samples under four different types of lighting conditions: store light (Department store light TL84), daylight (D65 (Class B)), home light (Incandescent light A), and store light fluorescent (Department store light CWF). The results for the average value and variation coefficient (CV, %) are shown in brackets hereinafter. As explained in Section 2.3, the coefficient of variation (CV%) was selected as a measure of repeatability due to its relevance in textile experimental research. Figure 5: Reflective ratio of the six textile samples with different knitting patterns under four lighting conditions. The letters A to F represent coded textile samples as defined in Table 1.  
The analysis based on the type of lighting conditions shows that the reflectance values range from 1.35 to 1.65, with higher values indicating better reflectivity. Under store light, the highest reflectance is observed in sample B (1.50, 2.99%) and sample C (1.42, 3.00%), while the lowest is found in sample F (1.35, 3.16%) and sample E (1.37, 3.11%). The difference between the best and weakest sample is 0.15, indicating a moderate effect of the knitting pattern on the reflectance. Under store light fluorescent, once again, samples B (1.60, 1.47%) and C (1.57, 1.49%) have the highest reflectance. The lowest reflectance is again observed in sample F (1.43, 1.63) and also in sample D (1.46). The difference is about 0.17, which shows a noticeable effect of the knitting structure on the reflective properties. Under daylight, the best reflecting sample is B (1.61, 2.25%), followed by C (1.55, 2.33%) and A (1.55, 2.33%). The weakest light-reflecting samples are F (1.45, 2.5%) and E (1.48, 2.44%). The difference of 0.16 shows that some textile knits perform better under natural light. When illuminated with warm light, typical for home lighting, the highest reflectance is found in samples B (1.48, 3.54%) and A (1.41, 3.71%), while the lowest is in C (1.38, 3.81%), D (1.38, 3.8%), and F (1.40, 3.75%). The reflectance is generally lower compared to other lighting conditions. The analysis of Figure 5 shows that sample B demonstrates the highest reflectivity under all lighting conditions, indicating that its knit pattern is the best for the reflective effect. Samples A and C also show high reflectance, but with some variations in different lighting conditions. Sample F exhibits the weakest reflectance in all tests, suggesting that its structure absorbs more light or contains fewer reflective threads. The fact is that the modified purl knit (Table 1) creates very large pores and fewer interlacings, which explains the lower reflective capacity of sample F.  
Fluorescent lighting and daylight provide the greatest increase in reflectance, meaning that the reflective threads perform better under these conditions. The coefficients of variation (CV%) indicate good to moderate repeatability of the measurements. The lowest values are observed under daylight illumination (2.25-2.50%), suggesting stable performance in natural light. The highest CV% values appear under home light (3.54-3.81%), indicating greater variability. However, all values remain below 5%, which is an acceptable range for experimental textile studies. Sample A exhibits the lowest overall CV profile, while sample F shows the highest. This highlights again that the choice of lighting conditions affects the consistency of reflectance measurements. The bar chart in Figure 6 shows the average reflectance ratio (RR\({}_{\text{av}}\)) of each sample under the four lighting conditions. The analysis of the results indicates that sample B (1.54) has the highest mean reflectivity. Therefore, its knit pattern is the most effective for light reflection. Samples A (1.49) and C (1.48) also show high reflectivity but are slightly lower than sample B. Samples D, E, and F have lower RR\({}_{\text{av}}\), indicating that their structure is less effective at reflecting light.