If you are a garment sewer, you are very familiar with grading your seams. The technique is commonly used to reduce bulk in seams that are straight or curved. It involves trimming one side of the seam allowance, making it smaller than the other side.
For instance, if your seam is a 5/8” seam, once you finish sewing you trim one side of the two layers about a ¼” smaller than the other side. This leaves you with one side of the seam at the original 5/8” and other side at the trimmed 3/8”.
This technique is not only useful in garment sewing. For quilting or home décor, or when using very heavy fabrics, grading seams can produce a much more professional looking project. Once pressed, the seam lies very flat.
Cutting away excess batting in the seams of a quilt as you go project gives a much crisper look to your seams. If you then pair grading seams with the use of a clapper, the results are wonderful. Lastly, if you are planning to sew a flat-felled seam, grading the seam will allow you to press everything to one side and get results that rival that of the best ready made clothing.