Better Homes and Gardens begins alterations with the bodice back. First they lengthen the bodice back so that the side seams are long enough. This is done with a slash and spread just above the tip of the waist dart. The first thing they look at then is the full back, which is what we are going to fit for today.
A Full Back adjustment may be required if the Bodice Back appears to be tight across the shoulders and there are pulls in the fabric under the arm scythe. This fitting issue is caused primarily by rounded shoulders, which means that the shoulder darts need increased shaping to fit properly.
|Deepened Dart (Orange)|
Next, determine how much width needs to be added at the shoulders. Reach your arms forward and around to insure that you will have a full range of motion. Then, check your side seams at the waist. If they also pull to the back then you need to add width to the waist. The amount required may be different.
Slash the Bodice Back from shoulder to waist, close the the arm scythe. Make sure you leave both of the darts intact. Spread the two pieces based of the measurements you took above. If the amount to be added is not the same at the waist and shoulder, angle the pieces so that more or less is added at the waist. However, they must be gently angled lines, not a curve, or sharp angles.
|Equal Adjustments (Left), Less Added to Waist (Right)|