Lesson 1
And I have filled him with the spirit of God, in wisdom, and in understanding, and in knowledge, and in all manner of workmanship,
Exodus 31:3
Why Patterns Have Lengthen and Shorten Lines
Look at almost any commercial pattern piece and you will find a pair of closely spaced horizontal lines crossing the piece, usually labeled lengthen or shorten here. Those lines are not decoration and they are not a suggestion. They mark the one place on that piece where the designer knows length can be added or removed without wrecking the shape of everything around it.
When Scripture describes Bezalel, it says God filled him with wisdom, understanding, knowledge, and all manner of workmanship. Understanding comes before workmanship in that list. Knowing why a line is printed where it is will save you more fabric than any clever trick with the scissors.
What the line protects
A pattern piece is a flat map of a curved body. The armhole, the waist curve, the hip curve, the crotch curve on a pant, and the notches that make two pieces match are all placed a fixed distance from one another. If you shorten a bodice by trimming an inch off the bottom, you have not just made it shorter — you have moved the waist curve up into territory shaped for the hip, and you have shortened the side seam so it no longer matches the back piece.
The lengthen/shorten line is placed in a straight, uneventful stretch of the piece: below the armhole and above the waist shaping on a bodice, above the knee on a pant leg, between the hip curve and the hem on a skirt. Change length there and every curve keeps its relationship to every other curve. The garment simply becomes taller or shorter.
Shortening: fold, do not cut
To remove length, decide the amount first — say 1 inch. Fold the pattern along the line so that the fold takes up half the amount you are removing, because a fold consumes fabric on both sides of itself. A 1/2 inch fold removes 1 inch of length. Crease it, tape it flat, and check the piece against a ruler to confirm you removed what you intended.
Lengthening: cut and spread
To add length, cut the pattern cleanly along the line, slide a strip of tissue paper or plain paper underneath, and spread the two halves apart by the full amount you want to add. An inch of spread adds an inch of length. Tape both halves to the filler paper, keeping the grainline arrow on the two halves perfectly parallel — if the pieces skew even slightly, the grainline breaks and the finished garment will twist on the body.
Redraw the seam lines, every time
This is the step people skip, and it is the step that shows. After folding or spreading, the cutting line at the side seam will step in or out at the alteration. Lay a ruler along the seam edge above and below the change and redraw one continuous line through the jog. On a straight seam a plain ruler is enough. Where the seam is already curved, use a French curve so the redrawn line flows rather than kinks.
The same rule applies to the front and back of the same garment. If you shorten the pant front by 3/4 inch and forget the pant back, the inseam lengths no longer match and you will fight that seam all the way to the hem.
Where to change length when there is no line
Some pattern brands print only one lengthen/shorten line on a long piece, and some vintage patterns print none. In that case, place your own line in the flattest part of the piece, well clear of any notch, dart point, pocket placement, or curve, and treat it exactly as a printed one. Draw it perpendicular to the grainline, not perpendicular to the side seam — those are not the same thing on a flared piece, and the grainline is the one that governs how the fabric hangs.
Common failures
- Removing length by trimming the hem of a flared skirt. The hem of an A-line skirt is wider than the hip; cutting an inch off the bottom leaves the skirt both shorter and narrower than intended.
- Folding by the full amount instead of half, and losing twice the length you meant to lose.
- Adjusting the front and forgetting the corresponding back, facing, lining, or pocket piece.
- Letting the two halves shift out of parallel while taping.
Work on the paper pattern with the pattern lying flat and weighted, keep your rotary cutter capped and away from the edge of the table while you tape, and label every piece you alter with the date and the amount changed. Six months from now that note is the difference between reusing the pattern and starting over.
Check yourself
What do the paired horizontal lines labeled 'lengthen or shorten here' mark on a pattern piece?
- The one place length can be changed without distorting surrounding shaping
- The finished hemline of the garment
- The location of the grainline arrow
- The seam allowance width
Answer
A. The one place length can be changed without distorting surrounding shaping
To shorten a pattern piece by 1 inch at the lengthen/shorten line, how deep should the fold be?
- 1 inch
- 1/2 inch
- 2 inches
- 1/4 inch
Answer
B. 1/2 inch
To add 1 inch of length, you should:
- Fold the piece 1/2 inch and tape
- Trim 1 inch from the hem edge
- Cut along the line and spread the halves 1 inch apart over filler paper
- Redraw the grainline 1 inch longer
Answer
C. Cut along the line and spread the halves 1 inch apart over filler paper
Why must the grainline arrow stay parallel on both halves when spreading a piece?
- It makes taping easier
- It keeps the pattern tissue from tearing
- It saves paper
- A skewed grainline makes the finished garment twist on the body
Answer
D. A skewed grainline makes the finished garment twist on the body
After folding or spreading, what happens at the side seam edge?
- Nothing changes
- The seam allowance doubles
- A jog or step appears that must be redrawn into one continuous line
- The notches disappear
Answer
C. A jog or step appears that must be redrawn into one continuous line
What tool should you use to redraw a seam line through an alteration where the seam is already curved?
- A French curve
- A rotary cutter
- A tape measure
- A seam ripper
Answer
A. A French curve
Why is trimming an inch off the hem of an A-line skirt a poor way to shorten it?
- It weakens the fabric
- The hem is wider than the hip, so the skirt ends up narrower as well as shorter
- It removes the grainline
- It cannot be pressed afterward
Answer
B. The hem is wider than the hip, so the skirt ends up narrower as well as shorter
If a pattern piece has no printed lengthen/shorten line, where should you place your own?
- Directly through a dart point
- At the hemline
- One inch below the armhole notch
- In a flat area clear of notches, darts and curves, drawn perpendicular to the grainline
Answer
D. In a flat area clear of notches, darts and curves, drawn perpendicular to the grainline
Exodus 31:3 lists wisdom, understanding and knowledge before which word?
- Beauty
- Workmanship
- Righteousness
- Charity
Answer
B. Workmanship
What is the most common oversight when altering pant length?
- Adjusting the front but not the matching back piece
- Using tissue paper instead of plain paper
- Working with the pattern lying flat
- Labeling the altered piece
Answer
A. Adjusting the front but not the matching back piece