Home sewists often find patterns they love, only to discover the sizing is too small. When a pattern does not match your body measurements, it is possible to safely enlarge it without distorting the garment’s intended shape. Three reliable methods exist for increasing a pattern’s size, suited for different adjustments, from targeted fit modifications to overall proportional scaling.
The Slash and Spread Technique
The slash and spread technique is a versatile method used to add volume or length to specific, targeted areas of a pattern piece. This approach is ideal for localized fit adjustments, such as increasing the bust circumference, adding length to a bodice, or widening a sleeve cap. The process begins by drawing parallel lines across the pattern piece in the area needing the size increase, such as across the bust line for a Full Bust Adjustment (FBA) or perpendicular to the grainline for length.
After marking the lines, carefully cut along them, stopping just short of the pattern’s edge to create a small paper “hinge.” This hinge keeps the pattern piece connected and maintains the original shape at the seam line. The cut sections are then spread apart by the exact measured amount required for the adjustment. Fresh paper is taped underneath to fill the resulting gap. For example, adding one inch of circumference to the bust requires spreading the pattern piece by a quarter-inch, because the pattern piece represents one-fourth of the total garment circumference.
Once the new paper is secured, the final and most important step is “truing” the pattern lines. Spreading the pieces often creates jagged or uneven edges along the cut lines, which must be smoothed out to ensure a continuous seam. Use a ruler or a French curve to redraw the seam lines, blending the new sections back into the original pattern lines. This smoothing process ensures the seam will lie flat when sewn, maintaining the garment’s intended curve and fit integrity.
Grading a Pattern to a Larger Size
Pattern grading is the technique used for proportional enlargement, systematically increasing the size of a pattern across all dimensions. This method scales the entire piece, not just a specific area. Grading relies on a set of standardized measurements, known as the “grade rule,” which dictates how much a pattern should grow at specific points between sizes.
For a single-size pattern, the process involves marking specific points, such as the neckline, shoulder, side seam, and hem. At these points, measure and mark the required grade amount, typically a small, consistent increment like 1/8 inch or 1/4 inch per size. For instance, the side seam might increase by 1/4 inch, while the shoulder line increases by 1/8 inch. These small increments are cumulative, resulting in the overall size increase when the garment is assembled.
If working with a multi-size pattern, the existing grading lines serve as a guide. Extend the established size lines outward, maintaining the same distance and curve relationship to plot the next size up. After marking all the new points, connect them using a straight edge or a curved ruler to create the outline of the larger pattern size. Precision is required to ensure the new lines are smooth and parallel to the original lines, maintaining the original design’s shape and fit.
Digital and Scaling Methods
For a quick, overall enlargement, digital and physical scaling methods offer an alternative to manual pattern manipulation. These techniques are best suited for patterns requiring a uniform increase across all dimensions, such as simple shapes or when the desired size is only one or two sizes larger than the original. A common approach is to use a large-format photocopier or a standard home printer with tiling software.
When using a printer, adjust the print settings to enlarge the pattern by a specific percentage (e.g., 110% or 125%). This causes the pattern to print across multiple tiled pages, which are then trimmed and taped together. Alternatively, a digital projector can project the pattern image onto a cutting surface, allowing the sewist to trace the pattern at a custom, enlarged scale directly onto the paper or fabric.
Regardless of the scaling method used, it is important to verify the accuracy of the enlargement. Most digital patterns include a one-inch or one-centimeter test square, which must be measured after printing or scaling. If the test square does not measure exactly the correct size, the pattern has been distorted, and the scaling percentage must be adjusted before cutting the fabric. This simple check ensures the pattern’s dimensions are correct and the final garment will be the intended size.