The threads support the stencil. The open areas allow ink passage. Familiarity with the meaning and importance of each mesh will make fabric selection easier---and consistent high-quality printing more predictable
Mesh Count:
The number of threads per linear inch (norminal mesh count). Screen fabrics are woven in threads per centimeter and then the number is calculated to English measurement for sale into parts of the world that don’t use the metric system
Example: A fabric woven at 120 threads/cm equals 305 threads/inch. The figure is calculated by multiplying 120 x 2.54=304.8, this number is rounded up to 305
Silk screening is enjoyed by many home hobbyists. But as a commercial and industrial printing method, it's a multibillion-dollar business. Although the process is now called "screen printing," as silk fabric for printing screens was replaced by polyester in the 1950s, the process is still commonly known as "silk screening."
Many beginners end up purchasing the wrong material, or mesh, for the job, resulting in bad prints and consequent frustration. But choosing the right mesh can be accomplished with a bit of painless education.