Textile professionals have specialized training and experience that allows them to evaluate the quality of fabrics with a more critical eye. Here are some factors that textile professionals consider when assessing the quality of fabrics:

Yarn quality

They may examine the quality of the yarns used to create the fabric, including factors such as yarn strength, evenness, and twist. Looking at the fabric you can assess the yarn eveness and fabric clarity.

Pilling resistance

The likelihood of the fabric developing pills (small balls of fiber on the surface) over time can be a sign of lower quality. This can also be assessed via various testing methods for pilling such as martindale abrasion, random tumble pilling, etc.

Shrinkage

Conducting shrinkage tests to determine how much the fabric shrinks is a common factor. If your mill is unable to generally control the same is a sign of weaker manufacturing ability.

Colorfastness

Conducting colorfastness tests to determine how well the fabric will retain its color over time and with exposure to different environmental conditions is extremely important. These include light fastness, washing, and water fastness. 

Staining on Multi-Fibre

Staining on multi-fibre refers to testing the bleeding which takes place on different fibre types when the fabric is introduced to water and washing. This mimics bleeding at customer end. This is a clear sign of poor quality fabrics.

Durability

This is the fabric’s ability to withstand wear and tear over time, which can be influenced by factors such as the fiber content, weave, and finishing. This can be assessed using comparing the tear, tensile, pilling, fastness of different fabrics.

Drape and hand

The way the fabric drapes and the way it feels to the touch, which can influence how it will look and feel when made into a garment or other textile product.

Fabric Appearance

There are no simple tests but assessing the sheen and shine on fabric is a good way to judge the quality of fabric. Colors should look deep and clean. Further, testing methods exist to evaluate the fabric look after a few washes.

Overall, textile professionals use a combination of factors to assess the quality of a fabric, and their experience and training will allow them to make more nuanced judgments about the fabric’s quality than someone without this expertise.