Piece dyeing is the default dyeing method for solid-color jersey t-shirts. The fabric is knitted, then dyed as a continuous roll — before it's cut into panels or sewn into garments. This gives you a uniform, consistent color across the entire production lot, with no variation between front, back, or sleeves.
The vast majority of basic and mid-range t-shirts are piece dyed. It's the most efficient method for solid colors at volume: one dye bath, one color lot, consistent results across thousands of units.
For solid-color t-shirts, spec piece dyeing with reactive dyes. It's the standard — consistent color, scalable production, cost-effective at volume.
Piece dyed vs. garment dyed
Reactive dyeing — why it's the right method for cotton
Reactive dyes form a chemical bond with cotton fibers — the dye molecule literally reacts with the cellulose in the fiber and becomes part of it. This makes reactive-dyed fabric highly wash-resistant and colorfast. The color doesn't sit on top of the fiber; it's embedded in it.
This is why reactive dyeing is the standard for cotton jersey. Acid dyes (used for wool and silk) don't bond to cotton. Direct dyes bond more weakly and fade faster. For a garment that needs to hold color through repeated washing, reactive is the correct choice.
Production specs for your tech pack
| Spec | Value | Notes |
|---|---|---|
| Dyeing method | Piece dyed | Fabric dyed before cutting and sewing |
| Dye type | Reactive | Required for cotton — forms chemical bond |
| Color reference | Pantone TCX | Specify code — e.g. 19-1664 TCX |
| Lab dip | Required | Submit before bulk dyeing — approve within ±0.5 ΔE |
| Color fastness | Min. Grade 4 | ISO 105 wash fastness standard |
| Lot consistency | Same dye lot | All fabric for one style in same dye batch |
In FlatLabs PRO, the dyeing method and color reference appear in the Fabric & Trims section of your spec sheet — including the Pantone TCX field, lab dip requirement, and color fastness standard.
The dye lot problem — and how to prevent it
Even within the same color reference, two dye baths produce slightly different results. This is normal — it's physics. The problem arises when a production run uses fabric from multiple dye lots: the front and back panels of the same garment can come out slightly different shades.
The prevention is simple: in your tech pack, specify "all fabric for this style to be from the same dye lot." This is a standard requirement. It limits the factory's ability to use remnant fabric from other runs, and it's the difference between a consistent product and one that has subtle color variation between units.