Pre-Washing and Preparing Fabric Before Cutting

Most fabrics are finished, dyed and rolled under tension, and many contain residual shrinkage that releases the first time they are washed or steamed. Natural fibers like cotton, linen and wool are especially prone, with some cottons shrinking several percent. A garment that shrinks after construction cannot be enlarged.

Pre-treating also removes manufacturing residues, sizing and finishes that can affect how the fabric sews and how the finished garment feels against the skin. Treating the yardage as you intend to launder the garment ensures the cloth is in its final stable state before you cut.

The guiding principle is simple: pre-treat the fabric exactly the way you will care for the finished garment. If you will machine wash and tumble dry, pre-wash and tumble dry the yardage. If you will dry clean, have the yardage steamed or dry cleaned, or at minimum press thoroughly with steam to relax it.

This consistency guarantees the cloth has already done whatever shrinking it will do under your chosen care regime, so the garment stays the size you sewed it.

• Washable cottons, linens, rayons: machine or hand wash and dry as the garment will be treated
• Wool and wool blends: steam press thoroughly or have professionally sponged; do not machine wash unless intended
• Silk: test a swatch first, as some silks water spot; many fine silks are best dry cleaned
• Synthetics: usually stable, but a wash removes finishes and confirms colorfastness

Deeply dyed fabrics, especially reds, indigo denim and hand-dyed cloth, can bleed. Before committing, wet a corner or swatch and press it against a white cloth to check whether dye transfers. Washing such fabrics separately, in cool water, with a dye-trapping sheet protects both the cloth and anything washed with it later.

Indigo denim in particular will continue to release dye for many washes; pre-washing once tames the worst of it and pre-shrinks the cloth at the same time.

After pre-treating, the fabric must be returned to a smooth, flat, stable state. Tumble or line dry as appropriate, then press out every wrinkle and fold crease with an iron at the correct temperature for the fiber. A center fold crease that will not press out can distort cutting, so reposition the fold if needed.

Pressing is not optional. Cutting wrinkled fabric introduces inaccuracy that no careful sewing can recover, because the pieces will be the wrong shape once the cloth relaxes flat.

Pre-washing can pull the grain out of true. Before cutting, check that the crosswise grain sits at a right angle to the selvage by pulling a weft thread or tearing across the width. If the grain is skewed, stretch the fabric gently on the opposing bias to coax it square, then press.

Cutting on a squared grain ensures that the grainline arrows on your pattern pieces, whether from a PDF tiled pattern or a plotted DXF AAMA file, align with the true lengthwise direction of the cloth and that the garment will hang correctly.

1. 1.Test a swatch for colorfastness and shrinkage if the fabric is new to you.
2. 2.Pre-treat the full yardage exactly as you will care for the finished garment.
3. 3.Dry the fabric using the same method the garment will see.
4. 4.Press out all wrinkles and stubborn fold creases at the correct temperature.
5. 5.Square the grain so the crossgrain is perpendicular to the selvage, then lay out and cut.