Altering paper patterns may seem complex and confusing, but in reality it is all based on very simple principles. Purchasing the correct size in the desired pattern is the most important step. Consult the Body Measurement section of this book for guidelines.
Paper patterns are flat, therefore any alteration made to the pattern must allow the pattern to lie flat or the garment will not fit or hang properly.
Consult the guide to Fitting Standards to determine how a garment should look. Measure the pattern pieces, allow for wearing and design ease present and compare with the body measurements. Note any additions or deletions to be made. Wearing ease can not be used instead of altering the pattern to larger measurements.
LENGTH ADJUSTMENTS comprise the bulk of pattern alterations done on commercial patterns. The basic bodice and skirt are illustrated, but the process is the same for any garment.
CIRCUMFERENCE ADJUSTMENTS incorporate several different techniques, depending on the amount to be deleted or added.
Small garment additions are done by simply adding to the outside edges of the pattern piece. Divide the amount to be added by the number of garment seams available. Do not include the CF and CB seams in this count. It is unwise to add to the CF and CB seams, since this affects the neckline as well. Once the measurement is arrived at, simply extend the pattern piece by that measurement in the area needed. Added fullness could be added to the entire side seam or the fullness could be added only at the waistline seam.
This type of pattern alteration will only success fully work when dealing with amounts of no more than 2" total.
The seams must be trued up by duplicating the curve/angle that was present in the original garment. The new seam line created must also match all other pattern pieces to be attached in length. Adding to a pattern, generally, lengthens the seam line, so some adjustment in the length of the garment must be done.
Large amounts of added fullness must be added to the pattern
using the slash and spread method. Once again divide the total
amount to be added by the number of body pattern pieces that it
can go into. The pattern is then slashed (cut) and a piece of
paper inserted. The pattern is spread the desired amount, taped
in place and any seam lines trued up.
Using the slash and spread method a great deal of fullness can be added to the pattern. Although, if more than 5"-6" is needed, the wrong size pattern was purchased.
Reducing the amount of fullness present in a pattern is done by
moving the seam line to the inside of the original seam line or
by folding and pinning the pattern to eliminate fullness. Once
again, divide the amount to be removed by the number of available
seams. Do not use CF or CB since this will make the neckline to
tight. If fullness has only to be removed from certain areas, at
the point of removal mark how far in to place the new seam line
Then draw a new seam line, tapering back to the original as
smoothly as possible. Fullness removed from the the waistline is
removed from both waist and hips. If the fullness has to be
removed from large areas, the pattern may sometime be folded and
pinned. The garment is reduced at the waist, hips and through the
skirt circumference. These folds follow the placement guideline
for slashing and spreading, and must not affect the neckline or
armseye. These folds will also affect the width at the bottom of
This page is the property of Scott R. Robinson and may not reflect the opinions of CWU nor any of its departments
Material on this web site may be used for educational purposed, if this footer is included.
Grateful appreciation is extended for all the links that assist in sharing this information with my classes.
All Rights Reserved © 2000 - 2010