Reading a spec sheet: width, weight, shrinkage

Every product page on this site lists composition, width and weight. All three are quoted the way the mill quotes them, which is not always the way a pattern room needs them.

Width is not usable width

A quality quoted at 57/58" is the full width off the frame. Selvedge, and the last centimetre at each edge where the weft density changes, are not usable. For cutting planning, assume 2 to 3 cm less per side on a woven.

This matters more than it sounds. On a 1,000-piece order, a 4 cm difference in usable width changes the marker and can push you from four garments per metre to three.

Weight has a tolerance

GSM is quoted on the greige, before finishing, and carries a tolerance — usually plus or minus five percent, sometimes more on a washed or brushed quality. A 150 GSM twill that arrives at 158 is not a mistake; it is inside the band. If your costing assumes the nominal figure, you will be short on the first delivery.

Ask for the tolerance in writing before you place the order, not after the first roll is weighed.

Shrinkage is a finish, not a fibre

Two cloths of identical composition can shrink differently because they were finished differently. A garment-washed viscose may lose 5% in the warp and still be within spec. A sanforised cotton may lose 1%.

This is why the pattern room should be told the finish, not just the fibre. Cut the bulk marker against the finished width, and add the shrinkage allowance to the length.

A short checklist

• Usable width, confirmed after finishing, not off the frame.
• Weight with its tolerance band stated.
• Shrinkage by direction — warp and weft separately.
• Finish name, so the sample room can reproduce the hand.

A spec sheet is not a description of the cloth. It is the set of assumptions the costing was built on.

We quote all four on request. It takes a day and saves a season.