Colour Fastness to Light
This method is intended for accessing the resistance of the colour of textiles to the action of daylight.
Principle: A specimen of the textile is exposed to the light from a Xenon arc lamp under prescribed conditions, along with eight dyed wool standards. The fastness is assessed by compared the fading of the textile with that of the standards.
Apparatus and Materials:
Humidity Test Control Fabric
Light fastness test apparatus containing a Xenon arc lamp (5500-6500°K), a light filter, heat filters and a black panel thermometer -
Grey Scale for assessing change in colour
Mount the specimen under test and the blue standards on a card, and mask the middle one-third (AB) of the test specimen and blue standards with opaque cover as shown in the following figure.
Expose the test specimen and blue standards to the xenon arc light. Cover one-third of the test specimen and blue standards with an additional opaque cover. After 20 hours, check the effect of light by removing the cover and inspect the specimen. Compare the test specimen with Reference number 4. Results and Assessment:
Comparing the visual contrast between the exposed and unexposed portions of the specimen under test with the corresponding portions of the blue standard 4 in standard viewing condition. We can see that the performance of the specimen is quite satisfactory as it scored a rating of grey scale 5, while the blue standard 4 has faded to grey scale 4-5. Conclusion and discussion:
In this test, there are certain factors that would affect the testing results. Inside the exposure chamber, a light filter is placed between the light source and the samples so that the ultra violet spectrum is steadily reduced. It must be well ventilated. While for the light box, the purpose of it is to provide light and standardize the simulated light for evaluating results. The D65 light used in the light box is to simulate the average sunlight. The colour used in the light box is grey which is a neutral colour. The angle of the assessment should be maintained at a same level which is 45 degrees. Test Samples:
Colour Fastness to Domestic and Commercial Laundering
This test is intended as a small scale, accelerated, laboratory test to predict the colour fastness of textiles to repeated washing using a soap solution.
A specimen of the textile in contact with specified undyed adjacent fabrics is agitated in a soap solution under specified conditions of time and temperature, then rinsed and dried. The change in colour of the specimen and the staining of the undyed adjacent fabrics are assessed using standard Grey Scales.
Apparatus and Reagents:
Stainless steel balls (approximately 0.6 cm in diameter)
Sodium hypochlorite or lithium hypocholorite
Sew a test specimen 10 cm x 4 cm to a standard multifibre fabric 10 cm x 4 cm, to form a composite specimen. Place the composite specimen in the container of the washing device and add the necessary amount of soap solution preciously heated to a specified temperature. Conduct the washing test on the composite specimen at the specified temperature for 45 minutes. Finally, remove the composite specimen at the end of the washing test and rinse twice for 1 minute in two separate 100mL portions of distilled water. For all methods, extract the excess water from the composite specimen. Open out the composite specimen by breaking the stitching on all sides except one of the shorter sides and dry it by hanging it in air at a temperature not exceeding 60°C, with the parts in contact only at the remaining line of stitching. Results and Assessment:
Assess with the Grey Scales the change in colour of the test specimen and the staining of the specified component of the multifibre fabric in...
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