Stain test is another fiber identification process. I have already written about the solubility test which is a chemical testing method. This type of test show the natural shades of the fiber. All the fibers have not same natural color and it can find out by treated the fibers with the drop of zinc chloro-iodide reagent.
Procedure Of Stain Test To identify The Textile fibers: Here, I have described about the stain test for identiy the textile fiber. Here it is-
- At first, different natural fibers are taken for test.
- A few fibers are placed on the microscopical slide.
- A drop of zinc chloro-iodide reagent is apply on the fiber and cover with a cover slip taking care to avoid bubbles.
- Examine the fibers for staining.
- By the observation, we will find the following results-
- Hemp, Ramie and cotton stain violet.
- Flax stain brownish violet.
- Jute stain brown.
- Many other fibers stain shades of yellow brown including silk.
- Warm a few fresh fibers on a microscopical slide with a drop of acid Phlorogucinol reagent.
- Woody fibers such as unbleached jute stain deep magenta because of presence of Lignin.
So, after observing the test sample we can decide about the fiber. It is most common process for know the natural shade of the fiber. Also, we can carry out density test, drying twist test and others for identify the fibers.