Image to embroidery file

How the picture becomes stitches

This is automatic digitising: software, not a person, decides where the needle goes. It is instant and repeatable, and it has limits, which are listed further down. What follows is exactly what it does, with the numbers, so you can judge the file before it goes near a machine.

1. Reading the artwork

The image is scaled so that one pixel is 0.1 mm of finished embroidery (up to 1,400 pixels on the long side), which is finer than a needle can place a stitch. An SVG is rendered at that resolution straight from the vector. The background is removed: transparent pixels, or the colour that dominates the frame, flooded in from the edges. Enclosed areas of that same colour are judged one by one: a convex blob is the counter of a letter and stays open, as does anything walled in by a thin line; a star, a glyph or a shape with corners is part of the design and is stitched. One setting stitches them all.

Colours are clustered in CIELAB and any two closer than about 11 ΔE become one thread, up to the limit you set (12 at most). Anti-aliased rims, JPEG halos and specks smaller than the minimum detail (0.4 mm by default) are absorbed into the shapes beside them, so they do not turn into extra colours or stray stitches.

2. Choosing a stitch type by measured width

3. What goes underneath

Every fill gets an edge walk 0.7 mm inside its outline, and fills larger than 30 mm² a tatami underlay sewn at right angles to the top stitching (3 mm apart, 2 mm on knits, fleece and towels). Rows are lengthened at both ends by the fabric's pull compensation. Each colour runs 0.3 to 0.5 mm under the colour stitched after it, so the fabric pulling in does not open a gap between them, and small shapes that sit wholly inside another colour, stars on a field or eyes on a face, are stitched on top of an unbroken fill rather than into a hole cut for them.

4. Order, travel and trims

Colours are sewn in order: large areas first, a fill before the border around it, a shape before what sits on top of it, outlines and lettering last. A colour used both underneath and on top, a dark ring and dark text on the disc inside it, is sewn twice with a thread change between. Inside a shape, the parts of a fill are joined by running stitches routed through the shape and sewn ahead of the rows that will cover them, instead of jumps. Between shapes the thread is tied off with two 0.7 mm lock stitches and trimmed when the move is longer than 1.5 mm. Penetrations closer than 0.3 mm are merged, and no stitch exceeds the 12.1 mm limit of the DST format.

Fabric presets change the stitches

Spacing and compensation follow the ranges digitisers publish for each fabric class (0.38 to 0.45 mm for wearables, 0.45 to 0.60 mm for leather and vinyl; 0.15 to 0.40 mm of pull compensation from denim to stretch knits). Needle and stabiliser are the usual starting points, not rules: your thread, backing and machine have the last word, which is why a test sew on scrap comes before the garment.

The audit is measured, not estimated

The production audit runs on the finished stitches: how much of the artwork is covered by thread, how many stitches land outside it, stitches under 0.3 mm and over 12.1 mm, the share of the area stitched too densely, trims per thousand stitches, and any detail that was too small to keep. The generator is built to pass these checks, so most designs score an A; when one does not, the row that lost points says what in the artwork caused it and what to change. The same file can be opened in the pre-flight check for a density heat map.

What it does not do well

• Photographs, gradients and soft shading. Thread is flat colour; a photo is reduced to posterised areas.
• Lettering under about 5 mm cap height, and lines under 0.4 mm. They are reported and left out, because they would not survive the fabric.
• Decisions that need taste: which way a fill should run to suggest fur, or where a highlight belongs. A human digitiser earns their fee there.
• Caps with detail near the seam, puffy foam, appliqué, metallic thread. These need technique that a generic file does not contain. For appliqué there is a dedicated tool: Appliqué Maker.

We validated this digitally: the stitch files are written by encoders checked byte for byte against reference files, and every design is measured by the audit above. We have not stitched every fabric preset on every machine, so treat the first run of any design as a test.