How do I tell the difference between knit and woven fabrics when choosing the proper backing?

Knit fabrics consist of a continuous strand of yarn or thread that is looped or knitted to create the fabric. It is stretchy in all directions and is considered an unstable fabric because of its long, continuous looping. Most sweatshirts, performance wear, and golf shirts would be examples of knits.

The threads that make up woven fabrics are crossed over and under each other on a loom at right angles, similar to the way a basket is woven. Except for a slight stretch on the bias (at a 45-degree angle), this type of fabric is generally not stretchy. Woven fabrics hold up to backing being torn from a design, so they’re considered stable fabrics. Examples would be denim jackets, canvas tote bags, and baseball caps.

—Madeira