
The first step for doing any kind of dart alteration is marking the bust apex. If you happen to be raising or lowering the darts (as in this case), you'll need to make a new apex mark fitted to your own figure, rather than using the one that is already printed on the pattern tissue. You can see the new mark that I made in the photo above -- it's a single blue dot.
Altering the Bust Dart (the dart protruding from the side seam):
1.) Slash the pattern in the shape of a backward "L." You can get a straight line for the long side of the "L" by drawing the line paralell to the grainline marking (unless the garment is bias-cut) or the center front line of the garment (see the solid green line in the photo above).
2.) Take a tuck at the top of the dart, bringing the point of the dart in line with the apex mark.
3.) Tape or glue the tuck into place.
Note: The same principles would be used to lower a bust dart, except your slash would be in the form of an upside-down and backward "L," and you would take the tuck under the dart.
Altering the Waist Dart (the dart prodruding from the waistline seam):
1.) Trace the waist dart onto a separate sheet of paper.
2.) Lay the bodice pattern piece over the traced dart, aligning the center lines of the darts (see red dashed line). Your pattern may not show the center line of the dart, but it is quite simple to draw your own.
3.) Position the point of the of the traced dart 1 inch below the new apex marking, and, keeping the centers of the darts aligned, trace the new dart onto the bodice pattern tissue.
4.) Use a ruler to straighten and connect the new dart legs to the starting points of the old dart legs.
After repositioning the darts, trace a new copy of the altered pattern, and true the side seams with a ruler, remembering to add new notches if necessary. It is also wise to test the fit of the new darts before cutting into your fabric.
I originally learned to make these pattern changes through the illustrations in the "alterations" section of the New Complete Guide to Sewing. Hopefully all of this makes sense. If it doesn't, just let me know!







