Indian Silk

Post Cocoon

Silk Testing

Colour Fastness of Textiles: Principles, Types, Importance and Testing

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This folder provides information about the silkworm seed sector, covering seed production, multiplication, distribution, and quality assurance for mulberry, vanya, eri, tasar, and muga silkworms.

/indian-silk/host-plant-cultivation-maintenance-breeding

This folder provides information on cultivation, maintenance, and breeding of host plants used for silkworm rearing, including mulberry, vanya, eri, tasar, and muga host plants.

This topic provides information about Muga Silk Dress Material.

/indian-silk/silk-mark-organisation-of-india-smoi-

This folder provides information about the Silk Mark Organisation of India, the apex body that certifies authenticity of pure silk products, including certification processes and consumer protection measures.

Provides list of awards in the Silk sector

This folder offers information related to India's silk exports and imports, including trade statistics, export destinations, import sources, tariff structures, and regulatory framework governing silk trade.

This folder provides information on publicity, media campaigns, advertisements, press releases, and awareness initiatives undertaken to promote the Indian silk industry.

/indian-silk/post-cocoon/weaving-and-fabric

This folder provides information on silk weaving and fabric production, covering handloom and powerloom technologies, traditional weaving techniques, design development, dyeing and printing, finishing processes, and production of diverse silk fabrics. It showcases India's rich weaving heritage along with modern innovations that support the handloom sector and commercial silk fabric manufacturing.

/indian-silk/post-cocoon/silk-testing/twist-and-twist-testing-in-silk-yarns-and-fabrics-principles-methods-and-influence-on-fabric-properties

Twist is the helical insertion of turns into a yarn around its longitudinal axis and is an important parameter controlling yarn strength, cohesion, flexibility, surface characteristics and fabric performance. 

/indian-silk/post-cocoon/silk-testing/air-permeability-and-water-vapour-permeability-of-textile-materials-with-reference-to-silk-fabrics

Air permeability and water vapour permeability are important comfort-related properties of textile materials that determine how effectively air and moisture vapour can pass through a fabric. In silk fabrics, these properties contribute significantly to breathability, moisture management, thermal comfort and wearing comfort. 

/indian-silk/post-cocoon/silk-testing/drapability-stiffness-and-crease-recovery-of-textile-materials-with-special-reference-to-silk-fabrics

Drapability, stiffness and crease recovery are important fabric performance characteristics that strongly influence the appearance, handle, comfort and practical usability of textile materials. In silk fabrics, these properties are particularly important because they determine the characteristic fluid fall, softness, elegance and wrinkle behaviour of the fabric. 

/indian-silk/post-cocoon/silk-testing/dimensional-stability-of-textiles-testing-of-shrinkage-and-expansion-with-special-reference-to-silk

Dimensional stability is the ability of a textile material to maintain its original dimensions during use, washing, wet processing, drying, ironing and exposure to moisture or heat. 

/indian-silk/post-cocoon/silk-testing/guide-to-testing-sorting-and-quality-control-of-mulberry-cocoons

This guide outlines the essential procedures for identifying, sorting, and calculating the defect percentage of mulberry cocoons to ensure high-quality raw silk production. 

/indian-silk/post-cocoon/silk-testing/gc-ms-and-hplc-for-detection-of-banned-azo-dyes-and-arylamines-in-textiles

GC-MS and HPLC are powerful analytical techniques used to detect and identify hazardous dyes and substances in textiles. 

/indian-silk/post-cocoon/silk-testing/colour-fastness-of-textiles-principles-types-importance-and-testing

Colour fastness refers to the ability of a dyed, printed or coloured textile material to retain its original colour when exposed to various external influences such as washing, rubbing, perspiration, light, water and heat. 

/indian-silk/post-cocoon/silk-testing/understanding-abrasion-and-pilling-resistance-in-silk-fabrics-silk-testing-2

This comprehensive guide explores how abrasion and pilling resistance determine the durability, smoothness, and luxurious appearance of silk fabrics.

/indian-silk/post-cocoon/silk-testing/ftir-spectroscopy-for-identification-and-characterisation-of-textile-materials

Fourier Transform Infrared (FTIR) spectroscopy is a rapid and non-destructive or minimally destructive analytical technique used for identifying and characterising textile fibres, polymers, finishes, coatings and other chemical constituents present in textile materials.

/indian-silk/post-cocoon/silk-testing/standard-for-raw-silk-grading-and-methods-of-tests

This Indian Standard (Parts 1 to 11) was adopted by the Bureau of Indian Standards towards grading and methods of test for raw silk.

/indian-silk/post-cocoon/silk-testing/understanding-raw-silk-grading-importance,-methods,-and-global-standards

Raw silk grading standardizes the quality of silk through rigorous physical and mechanical testing, ensuring fair pricing, processing efficiency, and reliable international trade. This comprehensive guide explores key testing methods and compares major global grading systems, including the Chinese, Japanese, and Indian standards.

/indian-silk/post-cocoon/silk-testing/tensile-strength-testing-of-silk-yarns-and-fabrics

Tensile strength is the maximum force a textile material can withstand when subjected to a gradually increasing tensile load before rupture. It is an important indicator of the strength, durability and service performance of silk yarns and fabrics. 

This folder provides information on silk testing, quality evaluation, and certification of silk yarn and fabric. It covers physical, chemical, and mechanical testing parameters, grading systems, standards and specifications, testing laboratories, and quality control measures that ensure authenticity and performance of Indian silk products in domestic and international markets.

/indian-silk/post-cocoon/reeling-mulberry

This folder provides information on reeling of mulberry silk, the process of extracting continuous silk filaments from cocoons. It covers traditional and improved reeling technologies including charkha, cottage basin, multi-end, and automatic reeling machines, along with re-reeling, yarn quality parameters, and best practices for producing high-grade mulberry raw silk.

This folder contains information on reeling of vanya (non-mulberry) silks including tasar, eri, and muga. It covers specialised reeling and spinning techniques suited to the unique cocoon characteristics of each vanya variety, along with improved machinery, yarn production processes, and quality standards for tasar, eri, and muga silk yarn.

This folder provides information on post-cocoon activities in the silk value chain, including reeling of mulberry and vanya silk, weaving, fabric production, and silk testing.

/indian-silk/international-and-foreign-affair

This folder provides information about International and Foreign affair

/indian-silk/by-products-and-value-addition

This folder provides information about by-products of sericulture and opportunities for value addition, covering utilisation of sericin, silkworm pupae, waste silk, and mulberry fruits and leaves.

Information about the Indian silk is provided

/indian-silk/capacity-building-and-training-cbt-

This folder contains information on capacity building and training initiatives for stakeholders in the Indian silk sector, including skill development programs, workshops, and training modules.

This topic provides information about Kancheepuram Silk Sarees

/indian-silk/banaras-cutwork-fabric-and-silk-saree

This topic provides information about Banaras Cutwork Fabric and Silk Saree.

/indian-silk/schemes-and-other-technical-information

This folder contains information about central and state government schemes, subsidies, and financial assistance programs for sericulture stakeholders, along with technical guidelines and advisories.

/indian-silk/silkworm-rearing-and-breeding

This folder provides information on rearing and breeding practices for different silkworm varieties, including mulberry, vanya, eri, tasar (oak), and muga silkworms, along with silkworm biotechnology.

This topic provides information about Arni Silk Saree

Oak Tasar Sericulture is a type of wild or forest based sericulture focused on producing a finer variety of Tasar silk using the temperate oak-feeding silkworm, called Antheraea proylei. The silkworm feed on leaves of various oak species (Quercus spp.), such as Q. serrata, Q. incana, etc. These are abundant in temperate/sub-Himalayan regions. Oak tasar culture is mainly practiced inNE & NW states of India. It provides livelihood opportunities, especially for tribal and rural for tribal and rural communities in hilly/forested areas, contributing to sustainable forest-based income generation.

<h3>Introduction</h3>
<p>Colour is one of the most important aesthetic and commercial properties of a textile. Consumers generally expect a textile product to maintain its original appearance throughout its useful life. However, dyes and pigments can undergo physical or chemical changes when textiles are exposed to washing, friction, perspiration, sunlight, water, heat and other environmental conditions.</p>
<p>Colour fastness is the resistance of a textile material to change in colour or to transfer its colour to another material when subjected to a specified external influence. It is therefore an important indicator of the durability and performance of dyed and printed textiles.</p>
<p>Colour fastness is not a single property. A textile may have excellent resistance to washing but relatively poor resistance to sunlight or rubbing. Therefore, different tests are required to evaluate its performance under different conditions.</p>
<h3>What is Colour Fastness?</h3>
<p>Colour fastness describes the ability of a coloured textile to retain its colour during use and care. Two principal effects are generally assessed:</p>
<ul>
<li>Colour change: Change in the original colour of the textile after the specified test.</li>
<li>Colour staining: Transfer of colour from the test specimen onto an adjacent multifibre or specified fabric during the test.</li>
</ul>
<p>Colour change and staining are assessed separately because a textile may show little visible change in its own colour while still transferring dye to another material.</p>
<p>The degree of fastness is influenced by several factors, including the type and class of dye, fibre type, dye&ndash;fibre affinity, dye concentration, method of dyeing, fixation efficiency, after-treatment and the conditions to which the textile is exposed.</p>
<h3>Major Types of Colour Fastness</h3>
<p><em>3.1 Colour Fastness to Washing</em></p>
<p>Washing fastness indicates the resistance of a coloured textile to colour change and colour transfer during laundering. It is particularly important for garments, bed linen, towels and other washable textile products.</p>
<p>Testing method: The textile specimen is washed under specified conditions of temperature, detergent, liquor ratio and mechanical action along with adjacent fabric. After drying, colour change and staining are assessed using standardized grey scales or instrumental methods.</p>
<p><em>3.2 Colour Fastness to Rubbing</em></p>
<ul>
<li>Rubbing fastness, also known as crocking fastness, measures the tendency of colour to transfer from a textile surface onto another material through friction. It is commonly evaluated under both dry and wet conditions.</li>
<li>Testing method: A standard white rubbing cloth is rubbed against the coloured specimen under specified pressure and number of cycles. The staining of the rubbing cloth is then assessed using a grey scale or instrumental evaluation.</li>
</ul>
<p><em>3.3 Colour Fastness to Light</em></p>
<ul>
<li>Light fastness indicates the resistance of a textile colour to fading when exposed to light. It is particularly significant for curtains, upholstery, outdoor textiles and garments exposed to sunlight.</li>
<li>Testing method: The textile is exposed to a controlled light source along with standardized blue wool references. The change in colour after exposure is compared with the reference scale to determine the light fastness rating.</li>
</ul>
<p><em>3.4 Colour Fastness to Perspiration</em></p>
<ul>
<li>Perspiration fastness determines the resistance of textile colours to human perspiration. Both acidic and alkaline perspiration conditions may be considered because perspiration composition varies.</li>
<li>Testing method: The specimen is placed in contact with specified adjacent fabrics, wetted with artificial perspiration solution and subjected to controlled pressure and temperature. Colour change and staining are evaluated after conditioning.</li>
</ul>
<p><em>3.5 Colour Fastness to Water</em></p>
<ul>
<li>Water fastness assesses the resistance of a textile colour to colour change and staining when exposed to water. It is relevant to garments and textiles that may come into contact with rain, water or moisture.</li>
<li>Testing method: The specimen and adjacent fabric are wetted with water, placed under specified pressure and maintained under controlled conditions. After drying, colour change and staining are evaluated.</li>
</ul>
<p><em>3.6 Colour Fastness to Sea Water</em></p>
<ul>
<li>Sea-water fastness is important for swimwear, beachwear and other textiles likely to come into contact with seawater.</li>
<li>Testing method: The specimen with adjacent fabric is treated with a specified artificial sea-water solution under controlled pressure and temperature. Colour change and staining are assessed after drying.</li>
</ul>
<p><em>3.7 Colour Fastness to Chlorinated Water</em></p>
<ul>
<li>This property is important for swimwear and textiles used in swimming pools because chlorine can cause fading or colour alteration.</li>
<li>Testing method: The textile is exposed to a specified concentration of chlorinated water under controlled conditions. The resulting colour change is assessed against an appropriate reference scale.</li>
</ul>
<p><em>3.8 Colour Fastness to Dry Cleaning</em></p>
<ul>
<li>Dry-cleaning fastness measures the resistance of textile colour to the chemicals and mechanical action encountered during dry-cleaning.</li>
<li>Testing method: The specimen is treated using a specified dry-cleaning procedure and evaluated for colour change and staining of adjacent materials.</li>
</ul>
<p><em>3.9 Colour Fastness to Ironing or Hot Pressing</em></p>
<ul>
<li>This test assesses the resistance of coloured textiles to colour change or colour transfer when subjected to heat and pressure during ironing or pressing.</li>
<li>Testing method: The specimen is subjected to specified temperature, pressure and contact conditions in dry, damp or wet states. Colour change and staining are subsequently evaluated.</li>
</ul>
<p><em>3.10 Colour Fastness to Heat</em></p>
<ul>
<li>Heat can cause migration, sublimation or chemical degradation of dyes. Heat fastness is therefore relevant to textiles subjected to ironing, heat setting, drying and other thermal processes.</li>
<li>Testing method: The coloured specimen is exposed to a specified temperature for a defined period, generally in contact with an adjacent fabric. The resulting colour change and staining are assessed.</li>
</ul>
<h3>Evaluation of Colour Fastness</h3>
<p>Colour fastness is commonly expressed using numerical ratings. In conventional visual assessment, grey scales are widely used.</p>
<p>For colour change and staining, ratings are generally expressed on a scale from 1 to 5, where:</p>
<ul>
<li>Grade 5 &ndash; Excellent fastness or negligible change/staining.</li>
<li>Grade 4 &ndash; Very good fastness.</li>
<li>Grade 3 &ndash; Good or moderate fastness.</li>
<li>Grade 2 &ndash; Poor fastness.</li>
<li>Grade 1 &ndash; Very poor fastness or severe change/staining.</li>
</ul>
<p>For light fastness, a separate standardized rating system, commonly based on blue wool references, is used.</p>
<p>Instrumental colour measurement can also be employed to quantify colour differences objectively, particularly where precise and reproducible assessment is required.</p>
<h3>Factors Affecting Colour Fastness</h3>
<p>Several factors influence the colour fastness performance of textiles:</p>
<ul>
<li>Type of fibre: Natural and synthetic fibres have different affinities for different classes of dyes.</li>
<li>Type of dye: Reactive, vat, disperse, acid, direct and other dyes exhibit different fastness characteristics.</li>
<li>Dye concentration: Excessive or poorly fixed dye may result in reduced fastness.</li>
<li>Dyeing conditions: Temperature, pH, time and liquor conditions influence dye fixation.</li>
<li>Fixation efficiency: Proper fixation of the dye to the fibre generally improves washing and other wet fastness properties.</li>
<li>Washing and after-treatment: Soaping, washing-off and other finishing treatments can remove unfixed dyes and improve fastness.</li>
<li>Textile finishing: Chemical and mechanical finishes may influence colour stability.</li>
<li>Exposure conditions: Temperature, humidity, light intensity, chemicals and mechanical action affect colour durability.</li>
<li>Fabric construction: Fibre arrangement, yarn characteristics and fabric structure can influence the extent of colour transfer and visual change.</li>
</ul>
<h3>Why is Colour Fastness Important?</h3>
<p>Colour fastness testing is important for both quality control and consumer protection. Its major significance includes:</p>
<ul>
<li>Ensures that textile products retain their appearance during normal use.</li>
<li>Reduces colour transfer between garments and other materials.</li>
<li>Helps determine the suitability of textiles for particular end uses.</li>
<li>Supports quality assurance during dyeing and finishing.</li>
<li>Helps identify problems associated with dye selection and fixation.</li>
<li>Minimizes consumer complaints and product rejection.</li>
<li>Provides a basis for comparing textile products from different manufacturers.</li>
<li>Helps manufacturers comply with customer specifications and applicable standards.</li>
<li>Supports export quality requirements and international trade.<br>Improves the service life and market value of textile products.</li>
</ul>
<h3>Colour Fastness and Textile Quality</h3>
<p>Colour fastness should be considered together with other textile properties such as tensile strength, dimensional stability, abrasion resistance, pilling, moisture management and chemical safety. A textile with attractive colour but poor fastness may rapidly lose its appearance during use.</p>
<p>Therefore, colour fastness testing forms an essential part of a comprehensive textile quality evaluation programme. The required fastness level should be selected according to the end use of the product. For example, outdoor textiles require high resistance to light, while frequently washed garments require good washing fastness.</p>
<h3>Standards and Test Methods</h3>
<p>Colour fastness tests are carried out according to internationally and nationally recognized test methods. Commonly referenced standards include ISO, ASTM, AATCC and BIS methods, depending on the product, customer requirement and intended market. Standardized test procedures are essential because factors such as temperature, pressure, detergent concentration, exposure time and mechanical action can significantly influence test results.</p>
<p>Laboratories should use appropriate reference materials, calibrated equipment, controlled environmental conditions and validated procedures to ensure reliable and reproducible results.</p>
<p><strong>Interpretation of Test Results</strong></p>
<p>A colour fastness result should not be interpreted in isolation. The acceptable grade depends on the intended end use, customer specification and applicable product standard. For example, a fastness grade considered acceptable for one product may be inadequate for another product subjected to more severe washing, rubbing or light exposure.</p>
<p>Both colour change and staining should therefore be considered while evaluating the overall colour fastness performance of a textile.</p>
<h3>Conclusion</h3>
<p>Colour fastness is a fundamental quality parameter that determines how effectively a textile retains its colour and resists colour transfer during use, care and environmental exposure. Since different service conditions affect textile colours in different ways, a range of fastness tests&mdash;including washing, rubbing, light, perspiration, water, sea water, chlorinated water, dry cleaning and heat&mdash;is required for comprehensive evaluation. Proper dye selection, controlled dyeing and fixation, effective after-treatment and standardized testing are essential for achieving good colour fastness. Reliable colour fastness testing ultimately contributes to better textile quality, longer product life, consumer satisfaction and compliance with market requirements.</p>