Question

1. After having dinner at a fancy restaurant furnished with navy blue table runner, you notice the sleeves of your white wool jacket has turned blue. What do you think caused this to happen? What standard test method would you use to evaluate the color?

Answer 1

The sleeves of the white wool jacket would have turned blue when it might have come under contact with the blue coloured table runner for a short but sustained period of contact, say 15-30 minutes. This would typically happen due to the dye from the table runner being diffused into the sleeves of the wool jacket. Wool has a higher absorption index for dyes as compared to silk or synthetic cloth material, making the dye to find a more stable dispersion medium and hence getting diffused from the table runner cloth to the wool jacket sleeves. Moreover, the initial white color of the jacket makes it an appropriate template to be observed readily when any other color was absorbed into it.

The standard test methods to evaluate the color could be through any of the following ways:
1. GC spectrophotometry: Take a small piece of thread from the segment of the sleeves which have absorbed the navy blue color. Prepare a sample out of it and cross verify with the dye present in the table runner cloth.

2. Dye extraction and titration: Extract the dye out of the sleeve of the wool jacket using leaching methods into an appropriate solvent. Titrate it with the indicator for the dye present in the table cloth runner and confirm the presence.

3. Soap test: Soak the fabric (the coloured part) into a soap solution for about 45 minutes and rinse. Observe if the dye is dispersed through the soap solution and confirm.