What is an embroidery design file?
An embroidery design, often called an embroidery matrix or pattern, is the set of instructions an embroidery machine follows to stitch an image onto fabric.
The short answer
A machine embroidery design is a digital file that tells the machine exactly where to put every stitch. It is a list of movements: move the hoop this far to the right and this far up, put the needle down, repeat. Along the way, the file also says when to jump to another area without stitching, when to cut the thread and when to stop for a new thread color.
Embroidery machines cannot read photos, PNG files or vector drawings. A person called a digitizer uses specialized software to turn artwork into stitches, deciding the stitch types, directions, density and the order in which everything is sewn. The result is saved in a format that a particular brand of machine understands, such as DST, PES or JEF.
What is inside the file
Most embroidery files contain some or all of the following:
- Stitch data: the sequence of needle points, usually stored as small relative moves in steps of 0.1 mm.
- Commands: jumps, trims, color changes and the end of the design.
- Thread colors: some formats store full colors and thread codes, some store an index into a brand palette, and some (like DST and EXP) store no colors at all.
- Header information: design size, stitch count, number of colors and sometimes the hoop it was made for.
- Previews: some formats include a small thumbnail for the machine screen.
The four basic commands
| Command | What the machine does |
|---|---|
| Stitch | Moves the hoop and makes a needle penetration. |
| Jump | Moves the hoop without stitching, to travel to another area or to split a long move. |
| Trim | Cuts the thread (or stops so you can cut it on machines without a cutter). |
| Color change | Stops for a new thread on single-needle machines, or switches needles on multi-needle machines. |
Every format encodes these same ideas in its own way, which is why designs can be converted between formats: the stitches stay the same, only the encoding changes.
Stitch files vs. working files
This is the most important distinction in machine embroidery.
- Stitch files (also called machine or expanded files) contain only the final stitches. DST, PES, JEF, EXP, VP3 and HUS are all stitch files. Machines sew them directly.
- Working files (also called native or outline files) are the editable masters saved by digitizing software, such as Wilcom EMB or Bernina ART. They store shapes and stitch settings, so the software can recalculate stitches when you resize or edit.
Tip
If you pay for custom digitizing, ask for both: the machine file to stitch, and the working file for future changes.
Why it is not an image
An image describes colors of pixels. A stitch file describes physical actions. The same picture can be digitized in many ways: with satin or fill stitches, with different angles, with or without underlay, for towels or for silk. Each choice changes how the design looks and behaves on fabric. This is why automatic conversion from a picture rarely gives a professional result, and why good digitizing is a skill.
Can I resize a design?
A little. In a stitch file, enlarging a design spreads the stitches apart and makes it look thin and gappy; shrinking it packs stitches together and can make it stiff, bulletproof and prone to thread breaks. As a rule of thumb, keep resizing within about 10 to 20 percent. Some software can recalculate stitch density when resizing a stitch file, which helps, but for bigger changes the best result comes from the working file or a new digitization.
Size, stitch count and time
Designs are described by their width and height, by the number of colors and by the stitch count. A small left-chest logo might have 5,000 to 10,000 stitches, while a large jacket back can exceed 100,000. Stitching time depends on machine speed: a home machine running at 600 to 850 stitches per minute takes roughly 12 to 17 minutes for 10,000 stitches, plus time for color changes. Commercial shops often price work per thousand stitches.