Making Sense of Pattern Grading
The most recent development, computer grading, is the fastest method, but tends to be an investment only larger manufacturers can afford. However, sophisticated home computer software is becoming affordable.
|Grading vs. alteration: What's the difference?
Grading is used to increase or decrease a size, based on an average difference between sizes. Alteration is used to make a particular size conform to an individual's personal figure challenges.
It's important to remember that grading only makes a shape larger or smaller and isn't intended to change a shape. Grading also reflects the fact that individuals of different sizes are proportionately different, not uniformly different. When we grade up or down, we don't merely make everything equally larger or smaller. Instead, we take into account that different body parts increase at different and proportional amounts.
Pattern vs. body measurements
The first step in any grading exercise is to accurately measure your base pattern. Sometimes you can find the key measurements you need (bust, waist, and hip) on the pattern envelope. Or you can measure the pattern itself.
To determine the actual measurements of the sewn garment rather than the size of the paper pattern, keep two things in mind when measuring a pattern. First, account for all design details. If a garment has a bust dart that extends to the waist, then omit the dart area when you measure the waist; similarly, omit the volume given to pleats and gathers. Second, measure the pattern from seamline to seamline, not cutting line to cutting line.
Once you've gleaned the key measurements from the pattern, you can address the basic grading dilemma-the difference between the pattern measurements and body measurements. To establish your body's bust, waist, and hip measurements, you can measure yourself or refer to the Quick reference for cut-and-spread pattern grading. To measure yourself, wear undergarments that fit well, and hold a measuring tape snugly (but not tightly) around your waist, the fullest part of your bust, and at hip level (9 in. below the waist). Before you record your measurements, be sure to add the amount of ease the pattern includes (or the ease yo'd prefer for that style of garment).
Establish the grade
Once you have the bust, waist, and hip measurements from both the pattern and your body, you can address the basic grading dilemma: "How much do I grade up if the pattern is too small? Or, if it's too big, then how much do I grade down?" To establish the overall grade, or the total amount needed to make the pattern larger or smaller, simply calculate the difference between the pattern and the body measurements. There are two types of overall grades: an even grade and an uneven grade.
An even grade means that the bust, waist, and hip measurements change the same amount from one size to another. For example, if a pattern measures 35-27-37 and the body measures 37-29-39, then the difference between each measurement is 2 in. and the overall grade is an even 2 in. Sizes of commercial patterns and apparel always follow an even grade.