Dimensional Stability

Dimensional stability gets measured in a lab the same way a customer discovers it in real life: wash the garment, dry it, then compare the new dimensions to the original spec sheet. Standard test methods like AATCC 135 and ISO 6330 run a knit through one or more home-laundering cycles and clock the percent change in length and width. A stable 100% cotton jersey typically lands at 3-5% residual shrinkage after that first wash; an unstable one can move 8-10%, and it usually doesn't move evenly in both directions.

That unevenness is what actually costs money on a reorder. We've had a client's full-front design come back from the wash with the bottom third of the art pulled a full inch closer to the hem than it left the press, because the tee's length shrank almost twice as fast as its width. Buyers rarely think about this until a customer emails a photo of a shifted logo. Cotton knits move more than poly blends, jersey moves more than a compacted or interlock structure, and a loose open-end yarn moves more than a tight ringspun one.

When you're specifying a blank for anything beyond a small left-chest print, pull the shrinkage tolerance off the tech pack before you commit to full-bleed or edge-to-edge art. Compacted, sanforized cottons in the 3-5% range are safe for oversized prints; anything rated above 6% needs the design pulled in from the edges so a shift doesn't run it off the seam.

The common mix-up is treating "preshrunk" as a promise of zero movement. Preshrunk and sanforized fabric still carries a residual shrinkage allowance — it's just been brought down from the 15-20% an untreated cotton knit could lose to the single digits a spec sheet will actually print.