The collar on this jacket is cut as a straight rectangle. The interfacing is shaped normally. The collar fabric is ease stitched with three rows of small basting stitches. It's pinned to the interfacing and the basting stitches used to gently ease the rectangle into the curved shape. Then the collar is steamed to shrink out the fullness and set the collar into shape. Here I've started easing the collar into shape using a steam iron to gently steam and then pat the fabric into shape.
The collar seam allowances are pressed down and basted, and the collar is hand sewn to the jacket body. The seam allowances are trimmed. The lining will be attached to the collar later. Hand basting really helps to fit the pieces properly, especially with this fabric that's prone to ravel and stretch.
I've decided the collar doesn't need trim.
