Pre-washing
Pre-washing is the process of washing fabric with water before sewing or use to check and adjust in advance for shrinkage, excess dye bleeding, and changes in texture.
Contents6 sections
Definition and Overview
Pre-washing is the preparatory step of washing purchased fabric with water before cutting and then drying it. Its purpose is to bring out shrinkage from moisture and any distortion in the grain in advance, reducing the risk that dimensions or shape will change after the finished item is washed.
It is especially considered when making garments that will be washed at home. Some fabrics are labeled as recommended for pre-washing, and in some cases it is required before use.
Changes in Hand and Appearance
After pre-washing, the effects of sizing and processing agents are reduced, and the fabric may become softer and more natural in hand than when purchased. On the other hand, the body, sheen, surface texture, and wrinkle appearance of the fabric vary depending on the material and finishing treatment.
Cotton and linen, for example, tend to shrink with moisture and may appear more compact after washing. Dark fabrics such as denim may release excess dye, so separate handling is standard.
Main Applications
It is done for items intended to be washed at home after completion, such as shirts, blouses, dresses, skirts, pants, and children's clothing. It is useful not only for spring and summer cotton and linen materials, but also for washable knit fabrics to check for shrinkage and distortion.
Not only for clothing, but also for bags and interior accessories, pre-washing should be considered before cutting if dimensional changes caused by washing may affect the finished result. However, depending on the combination with interfacing and other auxiliary materials, separate testing may be necessary.
Handling and Sewing Notes
The method of pre-washing should be matched as closely as possible to the washing method planned for the finished product. Check the care label, the fabric manufacturer’s notes, and the processing details, and do not carry it out at your own discretion on fabrics that are not water-washable or that are specified for dry cleaning.
After treatment, straighten the grain and cut only after the fabric is fully dry. If the fabric is still damp or not sufficiently dry, the dimensions will not be stable, affecting cutting accuracy and the shape after sewing. For patterned fabrics, also check for pattern distortion.
- To prevent color transfer, wash it alone the first time.
- Recheck the fabric width and required yardage before cutting.
- Not only the outer fabric, but also the same material used as a separate fabric should be treated under the same conditions.
- If using fusible interlining, perform an adhesion test on the pre-washed outer fabric.
Differences from Similar Terms
Pre-washing is the work of washing fabric with water before cutting. Hot-water treatment refers to processing with hot water, and it can cause stronger shrinkage and changes in hand than pre-washing, so judgment must be made according to the material.
Sanforizing is a treatment applied during fabric production to suppress shrinkage caused by washing. Even if the fabric has been sanforized, shrinkage may not be completely eliminated, so a trial wash is reassuring before mass production or important projects.
Frequently Asked Questions
Is pre-washing necessary for all fabrics?
No, it is not necessary for all fabrics. It is effective for garments that will be washed after completion, but it may not be suitable for materials that cannot be washed with water or fabrics with special coatings or finishes. Prioritize the care label and fabric handling instructions, and if in doubt, test on a scrap piece.
Does pre-washed fabric need to be ironed?
In many cases, the fabric is ironed while straightening the grain before cutting. If wrinkles or twisting remain, it becomes difficult to cut according to the pattern. However, for heat-sensitive materials or treated fabrics, check the temperature setting and whether a pressing cloth is needed, and avoid strong pressure.
Is pre-washing necessary for sanforized fabric?
Even if the fabric has been sanforized, if you want to check the dimensions and hand after washing, you can do a trial wash using a scrap piece. Follow the fabric’s care instructions, and check not only shrinkage but also color fading, wrinkles, bias distortion, and compatibility with fusible interlining before deciding on the main cut.
