I’m always amazed to see a rack of clothes of the same design in different sizes, all perfectly in proportion. How can one design in a size 2 look proportional to a size 14? Are separate sets of patterns made for each size? Are sizes consistent across brands?
Pattern grading is an unglamorous yet critical aspect of fashion design. Proper grading ensures that the original design is translated – without distortion – to smaller and larger sizes. The integrity of the design is maintained.
Each design is made up of a set of patterns – front and back bodices, sleeves, collars, etc. – in a sample size. Generally, the sample size – the starting point for grading – is in the middle of the desired size range, so there is the least amount of distortion when each pattern piece is graded.
A set of patterns for a sample of a French-style jacket. After the set of patterns for a design sample is finalized, a Pattern Record Card (PRC) is made to document all of the pattern pieces required; the number of each piece that needs to be cut in fabric, lining, etc.; and the notions (zippers, hooks, etc.) needed to complete the sample. These pattern pieces and the PRC are needed to begin the pattern grading process.
Patterns can be graded by hand with a pencil and a ruler, but these days digital systems are more efficient and accurate. Every pattern piece is digitized and sized up or down using specialized software. As a QC check, I like to sew up quick samples to make sure each size has been translated in proportion.
Digitized and graded patterns for the Curvy Coat, which is offered in sizes XS, S, M and L. The cat has QC'ed the graded patterns and approves!
Every designer has their own set of “grade rules” to guide the size ranges they offer. The increments between sizes can vary, which affects how one designer’s size small fits when compared to another. This variability is why it is so important to try on clothes to figure out which brand, in which size, fits you best.
Once the graded patterns are tested and approved, each pattern set in each size is printed (for custom or small quantities) or made into markers (for larger quantities). These patterns are then used to cut the fabrics!
A sample marker for the Crop Moto Jacket pattern pieces in sizes XS, S, M and L. All of the graded pattern pieces are arranged in the most economical layout to minimize fabric waste when cut. The fabric is stacked in layers to correspond with the number of pieces needed. A marker is a long piece of paper with the pattern layout printed on it that is placed on top of the fabric layers as a guide for the fabric cutter to allow large quantities of pattern pieces to be cut efficiently.