How to Read a Sewing Pattern

By | May 7, 2016

You’ve decided on a project, you’ve got a budget set, now it’s time to hit the books – pattern books, that is. Online and at the sewing store, there are hundreds of sewing patterns waiting for you to browse through them and take them home. But how can you tell which pattern will work best for your project?

There’s one simple thing you can do that takes a lot of the guesswork out of selecting a pattern: look at the line art.

Understanding The Lines

M6770_01_image

McCall’s 6770

M6770_lineart

McCall’s 6770 line art.

There’s a lot going on here with the ruffles and the patterned fabric. Look at the line drawing on the back of the envelope to see a much-simpler rendering of what the garment looks like and how it’s constructed. Not every pattern will have it, but anything put out by the Big Three – McCalls, Simplicity and Vogue – will feature a simple line drawing of the pattern, clearly showing where the seam lines are on the finished garments. These drawings follow certain industry standards and so you can rely on them to be quite accurate – even though it’s a little image only an inch or so tall!

Always examine the line drawing for indications where seams, shaping darts, pockets and closures are. Here are some examples comparing similar patterns with very different seam lines: three full-coverage bodysuits.

McCalls 7341

McCalls 7341

McCalls 7269

McCalls 7269

Simplicity 1036

Simplicity 1036

Next up, the lineart. (Click for bigger on all images.)

McCalls 7341 line art

McCalls 7341 line art

McCalls 7629 line art

McCalls 7629 line art

Simplicity 1036

Simplicity 1036

The seamlines for 7341 wouldn’t work Superman suit, but it also happens to be a very flattering cut for curvy women, and it’ll fit better, too (princess seams are awesome, even in knits).

Meanwhile, if you’re looking you’re looking to make a jester’s costume with a quartered motif then 7269 is the obvious choice. As you can see, the manufacturers clearly intended the pattern for Harley Quinn cosplay. That same pattern also includes a bodysuit with only a seam up the back, which is a starting point for a rig for Superman or Spiderman gear.

Meanwhile, Simplicity 1036 is a potential disappointment waiting to happen.

Based on the photo, you might think that you’re getting a one-piece bodysuit with a seamless front. But, looking at the line-art, you can see that it’s a two-part ensemble of pants and a top. As per the illustration, you can hide that with a belt or other garment over the waist, but that might not be feasible for what you have in mind. However, that pattern does have one advantage in that it requires less fabric than the single-seam-in-back style and that reduces the overall cost of the costume.

For bodysuits of any kind pay attention to how you’re supposed to get in and out of it. Is there a zipper? Where? Are you going to be able to still access that zipper under any embellishments on the costume? How will you go to the bathroom in it? Will you require help putting it on and zipping it up, or can you do it solo?

McCalls 6920

McCalls 6920

McCalls 6920 line art

McCalls 6920 line art

McCalls 7279

McCalls 7279

McCalls 7279 line art

McCalls 7279 line art

These dresses are the same length and have similar sleeve options, but 6920 uses a “princess” style line, while 7279 uses darts to give the garment it’s shape – that’s those little lines going from the side seam towards the bust. Conventional wisdom states that the princess seam is more flattering, but it can be more challenging to sew, because it’s a curved seam. It’s not crazy-difficult, just more difficult than sewing a dart which is (usually) just a straight line. It’s also trickier to alter on the fly – again, not impossible, but trickier.

Note that 7279 has a seam at the waist. This means the pattern uses smaller pieces of fabric and will require less yardage to assemble than if they were all of one piece in front, because you can cram a lot of little pieces onto your cloth more easily than long, sweeping panels. Less yardage means it’s cheaper to make.

How do you know how much fabric you need for a pattern? I’m glad you asked!

Envelope back for pattern 1538

Envelope back for pattern 1538

Picking Your Size and Determining Yardage

Here’s the back of the envelope for one of the shirt patterns already mentioned. This is where you determine what size pattern you need and how much fabric it will take. You’ve already had someone take your measurements, right? Of course you did.

Look at the size chart. On the Big Three, the guide is usually printed either on the back or on the flap of the pattern envelope. Use that to pick your size. If you’re between sizes, pick the next size up as it’s usually easier to take something in than to let it out. I often have to buy patterns that are too big in the hip, in order to fit my larger-than-average waist.

Caveat: if you’re feeling brave enough to try adjusting your sewing pattern, get your hands on a copy of Fit for Real People by Palmer & Pletsch and read their tips re: sizing from your high-bust measurement and adjusting a pattern to fit. But if you’re a beginner, let’s keep it simple.

Now find your size on the yardage chart. The exact amount of fabric will vary according to the width of the fabric you’re using. If you’re not sure if your bolt is 45” or 54” wide (the two most common widths in commercial fabrics, you’ll find 60” in the upholstery section) then ask at the cutting counter before anything gets cut. Read the instructions on the pattern envelop thoroughly. It will tell you if you need lining and/or interfacing – and how much of each. It will also tell you what you need in the way of zippers and buttons and suchlike, in the notions portion of the text.

If you expect your fabric to shrink when you pre-wash it, buy a little bit extra. When I’m sewing something from pure cotton, I get an extra quarter of a yard for every two yards dictated by the pattern, to allow for shrinkage. Plus I’m kind of terrible at laying out patterns. Even with the helpful diagrams.

I hope this hasn’t overwhelmed you but selecting a pattern doesn’t have to be a fraught process. Just keep looking at the line drawings, and you’ll find what you need. If you’d like some theme-specific pattern advice, you might want to check out these entries:

A (Very Brief) Introduction to Costuming for Renn Faire

A (Very Brief) Introduction to Costuming The Mid-19th Century

A (Very Brief) Introduction to Costuming the Late 19th Century

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