Color Fastness to Rubbing

Color fastness is the test that designed to determine the degree of color which may be transferred from one surface to another test specimen by rubbing (Both wet and dry).

There are two methods for Rubbing fastness.

1. ISO-105-X12
2. AATCC-08

In ISO-105-X12 the wet pickup of the rubbing cloth is 100%. In AATCC-08 the wet rubbing cloth will be 65% also we check rubbing in Dry cloth. In wet rubbing the wet the cloth as per the test method and give rating with the help of Gray scale. Similarly for dry rubbing we test the specimen by rubbing and then compare the staining and give dating with the help of grey scale.

     Color fastness to rubbing is the main test which is always required for every dyed or printed fabric. If the color fastness to rubbing result is good then its other properties like washing fastness and durability improves automatically because the rubbing is the test which test the fixation of color on a fabric.

      Generally rubbing fastness depends on "Nature of fabric color" and " Depth of the color".

Construction of the fabric nature is also plays a important role in Rubbing test. Like Pigment, Disperse, Direct has its own fastness properties to rubbing. There are few dark colors like Black, Navy, Red, Burgundy, Royal blue which have very poor fastness properties because of the chemical structure. Like black color is a carbon base color and the particle carbon size is larger than the other colors so the rubbing fastness is poor. Same for Red, Navy and blue colors also.

So, to improve the fastness more binder is added to improve the fastness of these colors. It doesn't mean that we cant able to improve the fastness to these colors. the required result can be achieved but the production cost will increase. On the other hand the construction of the fabric also gets effects the fastness properties.

The result we can get normally are like below.

                    Light colors                         Medium colors                           Dark colors
Dry                   5                                               4                                        3-4 & 4
Wet               4 & 4-5                                        3                                        2 & 2-3

GSM (GRAMS PER SQUARE METER)

Introduction

     GSM of the fabric is one kind of very important specification of fabric and it is very useful for Textile engineer to understand and production of fabric. GSM means "Grams per Square meter" that is the weight of the fabric in gram per one square meter. By this we can compare that fabric is heavier or lighter.

     The fabric weight can be determined in two ways. "weight per unit area" and "weight per unit length". In woven fabric, the weight per unit length is usually referred to as the "weight per running yard". It is necessary to know the standard agreed width of the fabric. Usually width of the fabric is based on Loom. Earlier before the term "GSM" is used as 1b/100 yards. This is British Standard. For measuring this we need "Templates" and "Quadrant Balance". The template area is 1/100 square yards of which each arm is 1/10 yards. For measuring GSM, GSM cutter is used to cut the fabric and weight taken by the help of Balance. Both of these methods are equally used for Woven and Knitted fabrics.

Procedure

1. For measuring with Quadrant balance, we need to prepare samples by cutting the fabric using template. 
2. Weigh the samples in  ponds with the help of quadrant balance according to 100 yards.
3. By this way we get the weight in ponds per 100 square yards fabric.
4. To obtain GSM, we need to cut the fabric by using GSM cutter.
5. Now weigh the sample by using Electric balance in grams.
6. By this way we get the weight in grams per one square meter fabric.
7. Now, find our the average of these found weight.

Dimension Stability

Dimension Stability :

     Dimension Stability is the testing that done to find out exact shrinkage of the fabric. This can be obtained by doing testing on Garment or fabrics. Internationally we have a specific method to find the shrinkage. Many 3rd party testing agencies are conducting this test and we can easily do this test in our home by just washing. yes, just a washing machine is enough to find he shrinkage of the fabric or garment.

     Now, let us see the procedure to find the shrinkage of the fabric.

1.  We need to measure the garments in length & width measurements.
2.  After measuring the garments put it for washing.
3.  After washing make it Flat dry or Hang dry
4. After drying remove the wrinkles by just pressing by hot steam (Ironing).
5.  Measure the same Length & width of the garment.

After doing the above steps we have to apply a simple formula to calculate the shrinkage. The formula for calculating the shrinkage.

 After wash - Before wash /  Before wash x 100

By applying the formula you can find the shrinkage of the Garment or Fabric.