GATE (TF) Textile 2013 Question Paper Solution | GATE/2013/TF/18

Washing fastness is a measure of how well a dye or pigment applied to a textile material can withstand repeated washing without fading or bleeding. It is an important property to evaluate the durability and quality of dyed or printed fabrics. There are various methods available for testing washing fastness in dyeing, and one commonly used method is the ISO (International Organization for Standardization) washing fastness test method.

The ISO washing fastness test method is described in ISO 105-C10:2016 Textiles – Tests for Colour Fastness – Part C10: Colour Fastness to Washing with Soap or Soap and Soda. The test involves washing the dyed or printed fabric samples in a solution of soap or soap and soda, followed by rinsing and drying. The degree of color change or color transfer from the fabric to the washing solution or adjacent fabric is then assessed and rated according to a standardized scale.
Here is a general overview of the ISO washing fastness test method:

Preparation of fabric samples: Fabric samples with the dyed or printed areas to be tested are prepared. Typically, multiple samples are tested, including reference samples with known fastness properties for comparison.
Preparation of washing solution: A solution of soap or soap and soda, as specified in the standard, is prepared. The concentration and temperature of the solution are controlled according to the specific requirements of the test.
Washing procedure: The fabric samples are immersed in the washing solution and agitated for a specified number of cycles or time duration. The agitation may involve mechanical rubbing or tumbling, simulating the typical washing process.
Rinsing and drying: After the washing cycle, the fabric samples are rinsed thoroughly with water to remove the washing solution, and then dried according to the standard procedure.
Assessment of color change or color transfer: The fabric samples are evaluated for any changes in color or transfer of color to adjacent fabrics. The assessment is typically done visually, and the results are compared to a standardized rating scale, which may include grades such as “5” for no change or transfer, down to “1” for severe change or transfer.
Reporting of results: The washing fastness results are reported based on the standardized rating scale, and the test may be repeated with different washing conditions or variations to evaluate the performance of the dye or pigment under different scenarios.
It’s important to follow the specific requirements of the ISO washing fastness test method and use appropriate equipment, materials, and procedures to ensure accurate and reliable results. Different standards or specifications may have slightly different procedures or rating scales, so it’s essential to refer to the specific standard being used for the testing.

Color fastness to washing in dyeing textiles refers to the ability of a dyed or printed fabric to resist fading, bleeding, or transferring color when subjected to repeated washing or laundering. It is an important property that indicates the durability and stability of the dye or pigment on the fabric surface during regular washing, which is a common part of the textile’s lifecycle.
Color fastness to washing is typically evaluated using standardized testing methods, such as those provided by international organizations like the International Organization for Standardization (ISO) or the American Association of Textile Chemists and Colorists (AATCC). These methods involve subjecting the dyed or printed fabric samples to a specified number of washing cycles or laundering conditions, followed by assessing any changes in color or transfer of color to adjacent fabrics.
Color fastness to washing is important in determining the quality and performance of dyed or printed textiles, as it impacts the fabric’s aesthetic appearance, durability, and serviceability. Fabrics that exhibit good color fastness to washing will maintain their original color and appearance even after repeated washing, without significant fading, bleeding, or color transfer. On the other hand, poor color fastness to washing may result in fabric color fading or bleeding, leading to a loss of aesthetic appeal, reduced durability, and potential staining of other fabrics during laundering.
Color fastness to washing is influenced by various factors, including the type of dye or pigment used, the fiber type, the dyeing or printing process, and the laundering conditions. Proper selection of dyes, appropriate dyeing or printing techniques, and careful laundering practices can help improve the color fastness to washing of textiles and ensure that they maintain their desired color and appearance throughout their intended use and laundering cycles.