For such a quiet little web site, my site does require quite a bit of work – hence the silence. I am happy to report that I’ve mostly won the battle and added lots to it in the past few weeks, both seen and unseen. There are now kits, needles, notions and a few books I’m enthusiastic about. Also had a wee sale on black Friday which was announced to newsletter subscribers only – I will continue to announce any price breaks solely there, so sign up if you’d like to be in the loop!
But, back to the subject at hand…
It’s been a while since I promised to write about grading, but it’s a lengthy subject and requires an uninterrupted block of time.
Before we can start about grading, let’s take a quick look at patterns and where they come from. When I speak about patterns, I don’t mean stitch patterns but rather the garment pieces garments are comprised of – what you see when you look at schematics. These are drafted using one of two methods: draping or the flat pattern method. Draping is done by pinning and positioning fabric on a dress form to develop the desired garment. I usually drape an a half size dress form, as can be seen in the photograph at the top of this post.
Flat patternmaking begins with what is known as a block or sloper – these are shells which fit the body with only wearing ease added. Sewing enthusiasts can purchase a pattern for one from one the four big pattern companies; in theory, any changes that must be made to it for fit would also be made to any pattern from the same company whether it is for length, width, etc. An example of a fitting shell can be viewed here.
Once a block has been perfected, it can be used again and again to create new styles by drawing new style lines. One could use the bodice alone to create the pattern for a vest – the neckline could be redrawn to a deep V, with length added below the waist and more wearing ease added throughout if needed. This is a very basic example, but I think you get the idea.
Once the pattern pieces have been perfected for the sample size, grading can begin. Let’s take a look at a front bodice to begin:
As you can see, the piece above represents only half of the front bodice. There’s no need to show both pieces as they are identical mirror images.
Succinctly, grading (or sizing) refers to extending the range of sizes garments are available in. The patternmaker takes the pattern drafted to fit the sample size and makes the adjustments needed so that it will fit smaller and larger sizes. It isn’t simply a question of blowing up the pattern a certain percentage – doing so would result in parts of the garment being ill-fitting as the shoulders and neck do not follow the same growth curve as the hip and bust do. The adjustments must been evenly distributed in a way similar to this:
The particular pattern piece shows what the grading would be for a difference of 1 1/2″ – the overall size grade can be seen by adding the three numbers at the very bottom and quadrupling them, since we can only see a quarter of the entire bodice. As you can see, the bust and waist are made bigger by the full 1 1/2″ while the shoulder width has increase only by 3/8″ across the entire width. The neck is slightly wider, gaining only 1/8″ across the width, but deepens a little as well by another 1/8″. The armhole is a little deeper, as is the length from underarm to waist.
I won’t bother showing a plain sleeve – I think you’ve all seen one of those before. Let’s see one being graded instead.
In the sleeve above, which is also graded for a 1 1/2″ difference in overall bust size, we see a few interesting things. First, the forearm and upper arm have different grading rules applied: the former gained only 1/4″ while the latter gained a full 1/2″. These are the only width changes – all the others confine themselves to the length, which needs to be added at the cap as well as at to the forearm and upper arm(note that the length of the sleeve was split in two both to allow for differing grades for the forearm and upper arm and to properly position an elbow dart, if needed). Which brings me to a little aside…
Over the years, I have heard many comments regarding length in knitting schematics. Often, knitters are under the impression that the only changes grading should bring to a pattern are to the width with perhaps some added length to the cap and armhole – the logic being that since patterns are graded to fit the same stature, they shouldn’t have added length through the body and sleeve. Sorry, but that’s wrong.
Girth does indeed add length to a pattern piece. Let’s do a little math – I know how much you all like math.
Let’s take two ovals – both are 10″ high but one is 5″ wide while the second is a perfect circle at 10″ wide. The circumference of the ellipse is 24.84 (no need to pull out your calculator, unless you want to – there’s an online calculator right here), while the circumference of the circle is 31.4. Even taking into account that the pattern piece only needs half of the the circumference to reach the top, we still have a difference of over 3 1/4″ in length. By the way, I’d like to apologize for not dressing any balls as proof. I’m too much of a slacker, I guess.
Anyhow. Spread it around, will you? I’m really tired of seeing patterns out there with the same body and sleeve length *for all sizes*.
Enough for that particular intermission. Back to grading.
I’m sure a few of the knitters will already have looked at the examples above and remarked that they are intended for cut patterns. That’s true, but I have yet to find a resource intended specifically for knitwear so used the logic above and converted to apply to knitwear using percentages and divisions. The full grade (1 1/2″) became my 100% while the other measurements were derived thusly:
Full grade: 100%
Front: 50%; full grade divided by 2
Back: 50%; full grade divided by 2
Shoulder Width: 25%; full grade divided by 4
Neck Width: 8.33% (*); full grade divided by 12
Side Depth: 8.33% (*); full grade divided by 12
Armhole Depth: 12.5% (*); full grade divided by 8
Neck Depth: 8.33% (*); full grade divided by 12
Wrist: 16.67% (*); full grade divided by 6
Bicep: 33.34% (*); full grade divided by 3
Sleeve Length: 16.67% (*); full grade divided by 6
Cap Length: 8.33% (*); full grade divided by 12
When I begin to grade a sweater, I begin by choosing my grading increment – in the case of a stockinette garment, I’d opt for a number divisible by 4 to make things easier. If it was a pullover knit at a gauge of 6 stitches to the inch, I might opt for a grading increment of 20 or 24 stitches. I probably wouldn’t choose an increment of 12 stitches as I’d then need too many sizes to run the gamut of 32″ to 50″ finished bust size – I feel it makes the pattern less legible as locating the correct size between a range of 6 (32″/36″/40″/44″/48/52″”) is easier than locating from a range of 11 or so sizes (32″/34″/36″/38″/40″/42″/44″/46″/48/50″/52″) . The fit can always be fine tuned by aiming for a gauge *slightly* looser or tighter than specified for in the pattern.
If my sweater was patterned, I’d have fewer choices as my stitch pattern would then dictate my grading increment. Whatever the increment ends up being, I convert it to an actual measurement and go on from there. A spreadsheet is invaluable for this, as a set of formulas divide the increment for each pattern piece and size, and the next set of formulas translate these measurements into stitches. Here’s an example:
This is just a portion of a spreadsheet, and it is something that no one else sees usually – it ends up being pretty messy, as I create formulas for any calculations I need along the way. You can see that the formulas suggest numbers impossible for knitwear (such as 143.9 stitches) – a line follows where I adjust the number into a whole one, and the following line indicates what measurement I should use on my schematic.
Where a spreadsheet really shines is at keeping track of small changes – imagine I was grading a sweater with a gauge of 4 stitches to the inch, for instance, and that my stitch pattern was 5 stitches wide. I’d probably have to opt for a grading increment of 5″ if I wanted to add 2 repeats of my stitch pattern on each front and back. The grading for the front and back would be easy, as each would need an additional 10 stitches per size. The neck width would be a different story, though, as each subsequent size would require an additional 0.41″, or 1.66 stitches:
With the help of the spreadsheet, I can use a little conjecture to decide where it’s acceptable to add a little extra width to the first, and where it is best to opt for a somewhat smaller opening.
Enough for today. If you’re still reading this (anyone?), here’s a little bibligraphy.
Grading Techniques for Fashion Design Second Edition – Jeanne Price & Bernard Zamkoff (the book I use the most, but OOP, unfortunately)
Pattern Drafting and Grading: Women’s and Misses’ Garment Design – M. Rohr (an old favorite; also OOP but the prices aren’t quite as high)
Concepts of Pattern Grading: Techniques for Manual and Computer Grading Second Edition – Kathy Mullet, Carolyn Moore & Margaret B. Prevatt Young (I haven’t read this one, but may for fun)
As always, ask any questions you may have in the comments!