Adjusting for a larger bust cup size is very easy when the pattern has a side bust dart, or in this case a contoured French dart. I favor this dart because it more mimics our actual bust shape and reduces the possibility of a “pointy” garment nipple.
Basically we just need a deeper dart intake to create a fuller “mound” pocket for the bust. My approach to a Full Bust Adjustment differs from style to style. My goal is to disturb the rest of the pattern as little as possible with the exception of increasing the “bust mound”. In this case, I wanted to keep my neckline and armholes true to their original shape, and I do not want to increase the waist or hip circumference. The assumption is that everything fit fine except needing more room in the bust mound.
Draw a straight line from the middle of the shoulder to the apex point marked on the pattern.
Draw straight dart legs from the apex mark to the ends of the French dart legs. Trace the contoured dart shape onto a scrap of paper and save this for later. We will now “slash” a cut through the shoulder line and pivot at the apex to “close” the French dart.
We will now draw a slash line from the apex to the center front neckline’s sew line. In this example, I wanted a full 1″ extra added to my dart, so I pivoted the end of each slash leg by 1/2″. You can increase as much as you feel you need to.
Next, draw the shoulder dart legs directly to the apex mark. Next, we will “close” the shoulder dart and open up the side bust dart.
Next we will take the tracing we made of the contoured French dart to use as a template to draw the dart legs back in.
Last step is we true up the shoulder line if it shifted a little.
We’re done! See the “before” and after?