WHAT IS GRADING A SEAM?
It is the process of turning a standard seam allowance into layered tiers of fabric. The result is less bulk, which means a smoother finish from the right side.
Grading a seam removes bulk and allows the seam to sit a little flatter on your finished garment. This is particularly useful when sewing with thick and bulky fabrics, like winter coats.
1. Turn your garment wrong side up so the seam is on top and open it out. Finger press it to stay open.
2. Decide which way you would like your seam to sit once it's finished (usually a seam is pressed toward the center back of a garment). In the example above we are going to press the seam to the right.
3. Simply trim the side of the seam that will sit underneath. In the example above we trimmed a 1.5cm seam allowance down to 6mm with pinking shears.
4. Press the un-trimmed side of the seam over top of the trimmed side to cover it. Your seam will now be noticeably thinner.
> In some cases you may be grading a seam that will be bagged out - for example, the collar of a coat. Simply press the entire seam back on itself (refer image below).