Don't depend on patterns to supply the turn-of-cloth
On blouses and dresses with a rolled collar, commercial patterns generally have only one pattern piece for both the upper and under collar. Turn-of-cloth is not taken into consideration. Even though patterns for tailored jackets and coats often have separate pattern pieces providing extra turn-of-cloth fabric for upper and under collars, it's often not enough nor in the right places.
|Some commercial patterns have a turn-of-cloth allowance built into their patterns, but make sure it's enough for the fabric you're using.|
Most commercial patterns also don't provide turn-of-cloth fabric at the center back of the upper collar, where it is needed most. Shawl collars are notorious for this problem. Facing pattern pieces on tailored jackets and coats generally have some turn-of-cloth built in such as the lapel pattern shown at left, but you need to make sure it's enough for the fabric you're using.
Fabric choice makes a difference
Even the best patternmakers cannot predict what weight fabric you'll use for the pattern. While you're checking for the right turn-of-cloth, you can also find other pattern errors. I've actually found patterns with smaller upper-collar patterns, which is obviously a patternmaker's error and could lead to sewing disappointments.
Understanding turn-of-cloth, checking the pattern, and knowing how to adjust it for your particular fabric will improve the quality of your fashion sewing.
Begin by determining fabric amounts
Heavier fabric requires more fabric for the turn-of-cloth.
Let your fabric tell you how much is enough. Cut two equal rectangles of your fabric approximately the width of the collar at the center back and interface as you will the collar. Pin the layers together along one edge as shown below. Then roll them over your hand and measure the difference that occurs between the free edges. This is the amount needed for the correct turn-of-cloth for this specific fabric. Add this amount to the center back on the upper collar and at the center back of the neckline edge, tapering to zero at the front ends. On light- to medium-weight fabric, 1/8 inch difference between the upper and under collars is usually enough to ensure the enclosed seams stay turned under.
|These two fabrics are the same size, but when one is curved over the other it appears smaller. The difference is the turn-of-cloth and the amount to trim from the underlayer.|