Underlay

You never see underlay, and that's exactly the point. Before a single visible stitch goes down, the machine lays a foundation pass — a simple edge walk, a crisscross zigzag, or a denser fishnet lattice — that grips the fabric and gives the top stitching something stable to sit on. Three underlay styles cover most of the work: edge walk for outlines, zigzag under light-to-medium fill, and fishnet under dense satin columns or 3D puff.

The garments where you feel the difference are stretchy ones — a tri-blend tee or a fleece hoodie with give in the knit. Skip underlay or skimp on it and a logo that looked crisp on the digitizing screen comes off the machine wavy, with letters that drift and edges that don't sit flush against the fabric. We've unpicked entire logos on jersey knits because a rush job dropped underlay to save fifteen seconds of machine time.

Digitizers vary underlay type and density by both fabric and the stitch type sewn on top of it — more underlay under a dense satin column, less under a light running-stitch detail, and a denser lattice specifically to fight push-and-pull distortion on knits versus wovens.

Buyers rarely ask about underlay because it's invisible, which is exactly why it's worth asking a digitizer about on a logo running on stretchy fabric — good underlay is a mark of a shop that digitizes for the actual garment, not just the artwork.