Pattern Grading: Proportionate Curves

Capture

The purpose of pattern grading is to change the size while keeping the proportions.  When a pattern is not graded correctly, the proportions become inconsistent between sizes.   This should be caught in alpha-testing; in beta-testing each sewist is making one sample, and isn’t concerned with consistency between her work and somebody else sewing a different size. But what if incorrect grading isn’t caught in alpha testing? What if you purchase a (non-returnable) pdf for the purpose of sewing matching sister outfits, and they don’t match? What if you sew to sell, and need consistency in shape between sizes? How do you adjust a pattern you’ve bought?

I was thinking about this recently…a very popular pattern that comes up a lot in discussions about fit issues is the darling “Clara” top from Violette Fields Threads. Since it’s a loose silhouette,  the only body measurement needed is chest size.  And yet there are fitting problems due to inconsistency in the grading  at all of the curves: the neckline, armscye, and shaped bodice waistline. Several customers have already asked about this within the VFT group online, and been advised that there are no problems. So, let’s analyze these 3 areas objectively, to see if there are grading issues, and also show how you can adjust your pdf at home.  Please note that I’m showing only small sections of a single pattern piece (the front bodice), NOT the entire pattern piece, which would of course be easier but  a violation of copyright laws.  For the purposes of product reviews, it is allowed to show sections of a copyrighted work.  All corrections made to the bodice front would need to be made also to the back.:

  1. Neckline: The colored rectangles represent the proportions of the neckline. The upper left corners are located at the stitching intersection of the shoulder seam and the neckline.  The bottom horizontal lines are located at the stitching line of the center-front neckline. So a quick glance at the rectangle shows you the overall proportion of each neckline after stitching.  In size 2 (red) the neckline width measures  double the neckline height. In size 10 (blue) the neckline width is about equal to the neckline height.  Grading has changed the size but not kept the proportions. In fact the size 10 is SMALLER across the neckline from shoulder point to shoulder point, than the size 2:

InsideNeckline

The stitching lines (without seam allowances) show 2 very different shaped necklines.  Size 2 is a shallow scoop with a slight vee at center,  size 10 has a deep rounded scoop:

NecklineShape

This is what the necklines look like on dressforms (2 on size 2 dressform on left, 10 on a size 10 dressform on right).  Size 2 is wide at the shoulder with a shallow curve, size 10 cuts into the neck and has a deep scoop:

neck

There’s no way to tell what the designer’s intention here is, however the inside-neckline measurement for the size 10 isn’t practical (it’s 4″ which is toddler-size), so we have to assume the shape of the size 2 is what the style is meant to have.  To make sure all sizes have this shape, the neckline needs to be re-graded.  Normally I would do this with a French curve on paper but for the sake of clarity I’ll show it to you on-screen but keep in mine that I do NOT know how to draft digitally, this is only to give a basic idea of HOW to adjust the pattern on paper.

Based upon the given inside neck measurement of 5″ for size 2, I’m estimating that 6 1/2″ is proportionate for size 10, so that’s where I’ll extend the inside neck line.  If I re-draw the size 10 neckline curve to 6 1/2″, the shapes look more consistent. The inbetween sizes would be drafted by dropping down from the intersection of the green line and the shoulder line for whatever size you need,  and connecting to the corresponding center-front of that size (then add  the seam allowances back in).  This is not difficult on paper when using your French curve:

Revised Neckline

………………………………………………………..

2. Armscye: the stitching line in size 2 has an extremely shallow curve and the bottom is not trued, so it will stitch up as a sharp “vee” shape, while the size 10 stitching line has an almost squared-off quarter-circle. Neither one approximates a standard French curve shape:

Armscye

This is how the armscyes look on dressforms (2 on left, 10 on right). Size 2 is very straight up-and-down with a “vee” at the side-seam and  minimal scoop to the front; it looks like it will chafe at the front underarm.  Size 10 is oversized:

arm

I don’t know which shape is the one the designer intended however since the shoulder line needed to be extended in the larger sizes anyway, due to  correcting the neckline, that’s a good place to start:

Amrscye2

When the size 10 armscye is adjusted to connect to the extended shoulder, the shape becomes closer to a French curve standard. Then when the size 2 is scooped out to mimic that same shape, they look more consistent and also more comfortable.  The inbetween sizes would be drafted by drawing a curve dropping down from the intersection of the top green line with the shoulder line for the size you want, and then connecting to the intersection of the bottom green line with the side-seam line for the size you want  (then add the seam allowances back in).  This is easy on your paper printed pattern, using a French curve.

Armscye3

……………………………………………………….

3. Bodice: the raised seamline connecting bodice to skirt has a shape detail that is not graded; it measures 4″ across and 1 5/8″ high no matter what size garment. This means the high-low effect will be quite pronounced in size 2 and less noticeable in size 10:

Bodice

For size 2, the raised shape is  1/3rd of the total garment width, and about 1/4th of the bodice height.  For size 10, the raised shape is  1/4th of the total garment width, and about 1/5th of the bodice height. To make the grade proportionate, it’s necessary to make a choice: does that curved line (above) belong to the size 2 or the 10?

To keep the size 2 (red line)  as-is,  draft  the blue line  for size 10, increasing the height of the raise shape  to 1/4th of the bodice height, and extending the width to 1/3rd of the bodice width:

Bodice2

To keep the size 10 (blue line) as-is,  draft the red line for size 2, decreasing the height of the raise shape to 1/5th of the bodice height, and shortening the width to 1/4th of the bodice width:

bodice4

If you are making a size between 2 and 10, use the red and blue lines as a visual guide and draft a new line inbetween them for the size you want.

….

And that’s it.  If you adjust the curved lines so that the sizes are changed while keeping the proportions, you’ll have a correctly graded pattern. You’ll be able to use the complete size range with consistent results.

 

 

 

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16 Responses to Pattern Grading: Proportionate Curves

  1. Sorahart says:

    Interesting stuff, thanks for sharing! I am enjoying learning more about the technical aspects of sewing–not just making pretty stuff. :)

  2. Bethany says:

    This is gold. Thank you! I’m printing it out. This is an area I have a lot to learn, and really want to learn. Thank you for taking the time to share this with us.

  3. Carrie says:

    Thank you I love the look of this but needed this fix! Now to enclose the ruffles! :-)

  4. Ashley says:

    Thank you so much!

  5. Catkin says:

    Thank you for this, I’ve learnt a lot just reading this post!! I don’t have the pattern in question myself, but am in many groups in which I see comments/questions. It is great that you’ve taken the time to help out and have explained everything so well that even a newcomer to pattern drafting can see/understand the issues. Thanks again.

  6. 7pinedesign@comcast.net says:

    Thank you, it’s hard to know sometimes how to explain stuff!

  7. 7pinedesign@comcast.net says:

    Thanks so much! I love playing with patterns….appreciate you reading this!

  8. 7pinedesign@comcast.net says:

    I think there are tutorials around for enclosing the ruffles….I agree, they look better that way!

  9. knitbunnie says:

    This is wonderful, and so are you! I’m about to venture into VF territory for the first time with a Maisie. Wish me luck! Thank you so very much for posts like this!

  10. Bunny says:

    Great blogpost. Thanks so much, Janet.

  11. Sharon says:

    Thank you Janet for another informative post! I signed up for your newsletter, looking forward to more excellent posts.

  12. RitaS says:

    I’m looking at your pattern grading for the curve of the armscye. The different sizes at the shoulder are parallel, but the lengths create an angle from which the armscye – french curve – hangs. How do you decide the angle with which to grade a pattern if the pattern doesn’t come with more than one size?

    Thanks!
    I’m a newbie to pattern grading, and must admit there isn’t much good info out there on the subject.

  13. 7pinedesign@comcast.net says:

    Not sure I understand your question….the angle from the shoulder to the armscye always starts at 90 degrees, both front and back, to create a straight line (180 degrees) after the front and back bodices are connected at the shoulder. I am going to write a post about using French curves on armholes, hopefully it will explain this more clearly.

  14. Rebecca says:

    Should an armscye curve always follow a French curve? As in, I can place my French curve along the armscye and not have to pivot it along the line to match it? I hope that makes sense. Thank you so much for blogging, I’m learning so much!

  15. 7pinedesign@comcast.net says:

    Hi Rebecca! Ideally, I like a French curved armscye, because that’s how I was taught. It’s in every pattern drafting book that I have, and it’s how all of my professors taught. The French curve is placed at the top and bottom of the armscye, and there’s your curve, voila!….it’s quick and easy. That said, depending on the width of the shoulders (the styling of the bodice), yes you might need to pivot the French curve. I have found that using a French curve is common in the U.S. and Europe, but not so much in Australia…there are many fine design colleges in Australia and some of my favorite patternmakers are in Australia, and I have heard from a couple of them that they never used a French curve in university nor in their practice, so it isn’t “required”.

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