Areca nut powder used as the natural dye source was obtained from Karnataka, India. Alum (potassium aluminum sulfate), corn starch, ferrous sulfate (FeSO₄), and copper sulfate (CuSO₄) were purchased from M/s S. D. Fine Chem Pvt. Ltd. Ready-for-dyeing (RFD) woven cotton fabric was procured from M/s Piyush Syndicate. The structural parameters of the cotton fabric, including ends per inch (EPI) and picks per inch (PPI), were recorded before experimentation.

Extraction of Areca Nut Dye

The dye extract was prepared using an aqueous extraction method. Approximately 10 g of areca nut powder was accurately weighed and mixed with 200 mL of distilled water. The mixture was heated and boiled until the volume was reduced to approximately 100 mL to obtain a concentrated dye extract. The resulting solution was filtered through bolting cloth to remove insoluble particles, and the filtrate was used for the preparation of the printing paste.

Pre-mordanting of Cotton Fabric

For mordanting, 5 g of alum was dissolved in 200 mL of water and heated until the volume was reduced to 100 mL to obtain a concentrated mordant solution. The solution was filtered before use.

The RFD woven cotton fabric samples were treated with this mordant solution at the boiling temperature for 15 minutes. After treatment, the fabric samples were removed, squeezed to eliminate excess liquid, and dried under ambient conditions. The pre-mordanted fabric was then used for subsequent printing experiments.

Preparation of Print Paste and Experimental Design

A starch-based print paste was prepared using 10% corn starch as a thickening agent, into which the previously prepared areca nut dye extract was incorporated. The paste was thoroughly mixed to obtain a uniform consistency suitable for printing.

To investigate the influence of different metal salts on shade development and color fastness, the prepared print paste was divided into two equal portions. In one portion, copper sulfate (CuSO₄) was added, while in the second portion, ferrous sulfate (FeSO₄) was incorporated.

Thus, three experimental conditions were evaluated:

Sample A:Cotton fabric pre-mordanted with alum and printed with areca nut dye paste (control).

Sample B:Alum pre-mordanted cotton printed with areca nut dye paste containing copper sulfate.

Sample C: Alum pre-mordanted cotton printed with areca nut dye paste containing ferrous sulfate.

Each experiment was conducted with replicate samples to ensure the reproducibility of the results. During the study, key parameters such as fabric type, mordanting conditions, dye extraction method, printing procedure, drying temperature, and steaming conditions were kept constant so that the effect of the metal salts could be clearly evaluated.

Printing and Fixation

The prepared print pastes were applied to the pre-mordanted cotton fabric using a laboratory printing method. After printing, the samples were dried at 120˚C, followed by steaming at 105˚C for 20 minutes to facilitate dye fixation. The printed fabrics were subsequently washed thoroughly with water to remove unfixed dye and thickener, and then dried before further evaluation.

The printed fabric is tested for various fastness properties, such as washing, rubbing, and light fastness. Similarly, shade was also evaluated by K/S values using a computer colour matching system.

Fastness to washing (C01-C06)

Sample preparation

Washing fastness was determined according to the ISO 105-C01 standard. The test specimen was prepared by sandwiching the printed cotton sample between two undyed adjacent fabrics, one cotton and one wool.

The composite specimen was washed in a launder-ometer under the prescribed conditions of the standard. After washing, the specimens were dried and evaluated for color change and staining using the grey scale rating.

Fastness to light

Light fastness was evaluated according to ISO 105-B02 (Xenon arc lamp method). The test specimen and a set of eight blue wool reference standards were mounted together.

One third of the specimens were exposed to the xenon arc light source for 24 hours, while the remaining portion was covered. After exposure, the fading of the specimen was visually compared with the blue wool standards and rated accordingly.

Fastness to rubbing.

Rubbing fastness of the printed fabrics was evaluated according to ISO 105-X12 using a crock meter. Both dry and wet rubbing tests were carried out. In this method, the printed specimen was mounted on the rubbing tester and rubbed against a standard white cotton cloth under controlled pressure and several rubbing cycles. For wet rubbing, the rubbing cloth was wetted with distilled water before testing.

After the test, the staining of the rubbing cloth was assessed using the grey scale for staining, and the results were reported accordingly.

Fastness to perspiration

Perspiration fastness was determined according to the ISO 105-E04 standard. The printed specimen was placed between adjacent undyed fabrics and treated with acidic and alkaline perspiration solutions.

The composite samples were kept under controlled pressure and temperature for a specified duration. After treatment, the specimens were dried at room temperature and evaluated for color change and staining using the grey scale rating.

This test measures the resistance of printed colors to washing, which is a key factor for the durability of textiles in real-life usage. The test followed ISO 105-C01 standards, using a launderometer or washing machine at 40˚C for 30 minutes with standard detergent. The printed samples were stitched to cotton and wool fabrics to check for staining, and gray scales were used to evaluate both color change and staining. Both Areca nut dye prints were tested with alum, FeSO₄, and CuSO₄ mordants. The results showed that the prints had moderate to good fastness ratings. Alum-mordanted samples displayed better performance, especially when tested on cotton, with minimal staining and less noticeable color change. FeSO₄ and CuSO₄ showed more staining on wool fabrics, indicating slightly lower fastness. Overall, washing fastness was acceptable, with alum-mordanted samples showing the best balance of stability and resistance [15].

As summarized in Table 1 and shown in Figure 1, the washing fastness results indicate that the type of mordant significantly influences the durability of the printed color on cotton fabric. Among the three mordants, alum exhibited the best performance, showing good fastness ratings on both cotton (4)-(5) and wool (4), which suggests minimal color change and staining. In contrast, fabrics treated with FeSO₄ showed moderate fastness on cotton (3)-(4) and only fair performance on wool (3), indicating increased color bleeding, especially on protein fibers. Similarly, CuSO₄-treated samples demonstrated moderate fastness on cotton (3) and fair performance on wool (2)-(3), reflecting comparatively lower resistance to washing. Overall, alum proved to be the most effective mordant in maintaining color stability during washing, followed by FeSO₄ and CuSO₄.

Figure 1.Image containing the test evaluation, Washing to Fastness test.

Table 1. Rating of fastness to washing tests.

The rubbing fastness test evaluates how well the printed color resists rubbing, both in dry and wet conditions. This is important to assess how the fabric will behave during wear and use. The test was conducted using a crockmeter with a white test cloth. For dry rubbing, the sample was rubbed 10 times using a dry white cloth, and the amount of color transferred was evaluated using a gray scale ranging from 1 (poor) to 5 (excellent). In wet rubbing, the same procedure was repeated, but the cloth was first wetted with water before rubbing. Results varied depending on the dye and mordant used. Areca nut dyes were tested with three mordants: alum, ferrous sulfate (FeSO₄), and copper sulfate (CuSO₄). Generally, alum-treated samples showed better rubbing fastness than those treated with FeSO₄ and CuSO₄, particularly in dry conditions. However, wet rubbing fastness was slightly lower across all samples, which is typical due to the dye’s tendency to bleed when moisture is present [16].

Figure 2.Image containing the test evaluation, rubbing to fastness test.

As presented in Table 2 and illustrated in Figure 2, the rubbing fastness results show a clear dependence on both the mordant used and the testing condition (dry vs. wet). Alum-treated samples exhibited the best performance, with good dry rubbing fastness (4)-(5) and moderate wet rubbing fastness (3)-(4), indicating strong dye fixation and relatively low color transfer. In comparison, FeSO₄-mordanted fabrics showed moderate resistance in dry conditions (3)-(4) but only fair performance in wet conditions (2)-(3), suggesting increased dye bleeding when moisture is present. Similarly, CuSO₄-treated samples demonstrated moderate dry rubbing fastness (3) and fair wet rubbing fastness (2)-(3), indicating comparatively weaker dye adherence. Overall, the results confirm that rubbing fastness is generally higher in dry conditions, while wet conditions reduce performance due to the increased mobility of dye molecules, with alum providing the most stable results among the tested mordants.

Table 2. Rating of fastness to rubbing tests.

Results showed that Areca nut dyes both responded differently to light depending on the mordant used, as summarized in Table 3. In general, CuSO₄-treated samples exhibited slightly better resistance to fading, while alum and FeSO₄ showed moderate light fastness. The dye samples had slightly higher grades overall compared to Areca nut, especially when alum was used. This test confirmed that while natural dyes can fade under prolonged exposure, selecting the right mordant can significantly improve their stability under light [17]. The visual assessment of light fastness for different mordants is shown in Figure 3.

Figure 3.Image containing the test evaluation of light fastness test.

The light fastness results indicate that the resistance of the printed fabrics to fading under light exposure varies with the type of mordant used. Among the tested samples, CuSO₄ exhibited the best performance with a good rating (4), suggesting enhanced stability of the dye under light conditions. Alum-treated fabrics showed moderate light fastness (3)-(4), indicating acceptable resistance to fading with relatively stable color retention. In comparison, FeSO₄-mordanted samples displayed slightly lower performance with a moderate rating (3), suggesting a higher tendency for color degradation upon prolonged light exposure. Overall, while all mordants provided acceptable light fastness, CuSO₄ proved to be the most effective in improving resistance to photodegradation.

Table 3. Rating of fastness to light tests.

The color characteristics of cotton fabrics printed with areca nut extract were analyzed using a spectrophotometer. Measurements included CIE tristimulus values (X, Y, Z), CIELAB coordinates (L*, a*, b*), chroma (C*), hue angle (H*), and color strength (K/S), calculated according to the Kubelka–Munk theory at the wavelength of maximum absorption (λmax).

The alum-mordanted sample exhibited a moderate K/S value (10.24), corresponding to a medium shade depth. Its L* value (69.63) indicated a relatively light tone, while positive a* (9.148) and b* (15.337) values confirmed a red–yellow hue, giving a warm orange-brown appearance. The chroma (C* = 17.858) suggested moderate color saturation, and the hue angle (H* = 59.162˚) further verified the orange-yellow character of the shade.

The FeSO₄-mordanted fabric showed the highest K/S value (23.843), indicating the deepest shade. Its slightly lower L* value (66.671) reflected a darker tone, and the reduced a* (2.44) and b* (3.634) values suggested a muted red-yellow intensity. This deeper brown color is attributed to the stronger interaction between iron ions and the dye molecules, which enhances dye uptake and color fixation.

In comparison, the CuSO₄-mordanted fabric had the lowest K/S value (5.053), indicating a lighter shade. The higher L* (69.866), a* (8.608), and b* (16.087) values demonstrated greater brightness and more vivid red-yellow tones, resulting in a lighter, warmer orange-brown appearance.

These findings confirm that the type of mordant strongly influences shade depth and chromatic properties: FeSO₄ produces the darkest, more muted shades; alum yields intermediate shades; and CuSO₄ generates lighter, brighter tones. Overall, areca nut dye can impart visually appealing and technically satisfactory colors on cotton fabric, with mordant selection providing a practical method to adjust shade intensity and hue for sustainable textile printing applications.

The spectrophotometric analysis of cotton fabric printed with areca nut dye and mordanted with ferrous sulfate (FeSO₄) revealed distinct colorimetric characteristics compared to alum-mordanted or CuSO₄-mordanted samples. The tristimulus values were X = 35.019, Y = 36.198, and Z = 35.967, indicating a slightly darker and cooler tone. The L* value of 66.671 shows a subtle reduction in brightness compared to the alum-mordanted sample (L* = 69.63), suggesting a mild darkening effect imparted by FeSO₄. The a* (2.44) and b* (3.634) values indicate a significant decrease in red and yellow contributions, resulting in a cooler, more subdued orange-brown shade. The chroma(C= 4.377)* further confirms a duller, less saturated color, while the hue angle(H= 56.099˚)* positions the shade in the muted orange-yellow range. These changes align with the known behavior of ferrous sulfate to subdue the warmth of natural dyes, often producing earthy or muted tones, making it particularly useful when deeper and less vivid colors are desired.

Despite the lower saturation and muted hue, the K/S value reached 23.843, more than twice the value observed in alum-mordanted fabric (10.24), reflecting stronger dye uptake and enhanced color depth. The reflectance (RFL = 20.411%) and total absorption energy (232.829) support this observation, indicating that the fiber absorbed more dye and retained a darker, richer shade. The Δ-values further quantify the effect of FeSO₄: ΔL* = –2.959, Δa* = –6.708, Δb* = –11.703, highlighting decreases in brightness and red-yellow intensity, while ΔC* = –13.481 and ΔH* = –0.473 confirm reduced chroma and minor hue shifts. The total color difference, ΔE* = 13.81, underscores a perceptible change in shade compared to alum-mordanted fabric. Overall, FeSO₄ mordanting produces darker, deeper, and more earthy tones, demonstrating a strong dye-fiber interaction that enhances color depth while moderating visual saturation, making it an effective choice for creating rich, muted shades in natural dye printing.

The spectrophotometric evaluation of cotton fabric printed with areca nut dye and mordanted with copper sulfate (CuSO₄) revealed a bright and visually appealing shade with distinct colorimetric characteristics. The tristimulus values were X = 41.188, Y = 40.559, and Z = 30.838, indicating high brightness and moderate color depth, closely resembling the alum-mordanted standard. The L* value of 69.866 confirms that the fabric retains a light to medium-light tone, slightly higher than the FeSO₄-mordanted sample, suggesting enhanced luminance. The a* (8.608) and b* (16.087) values indicate strong contributions of red and yellow, producing a vivid and warm hue. The chroma(C= 18.245)* is slightly higher than the alum-mordanted fabric (C* = 17.858), reflecting enhanced color saturation, while the hue angle (H= 61.824˚)* positions the shade in the orange-yellow region, characteristic of areca nut but with slightly more brilliance than alum.

The difference values demonstrate minimal shifts from the standard: ΔL* = 0.954 shows almost identical lightness, Δa* = 0.236 indicates a slight increase in redness, and Δb* = –0.540 reflects a small reduction in yellowness. The total color difference (ΔE = 0.75*) confirms a close match to the standard, while ΔC* = 0.387 and ΔH* = 0.839 suggest minor increases in saturation and negligible hue change. The K/S value of 5.053, lower than FeSO₄ (23.843) and alum (10.24), indicates moderate dye absorption, consistent with the higher reflectance (RFL = 39.692%) and lower absorption energy (202.668). These observations confirm that CuSO₄ mordanting produces a lighter, cleaner, and more luminous shade with excellent visual clarity. Overall, while FeSO₄ yields deep, earthy tones and alum provides balanced vibrancy, CuSO₄ offers a bright, orange-yellow hue with moderate depth and high aesthetic appeal, making it suitable for applications where lighter and more vivid natural dye shades are desired.