Showing posts with label Grade rules. Show all posts
Showing posts with label Grade rules. Show all posts

July 20, 2022

The Essential Guide to Children's Clothing Sizes and How to Grade Them

I am excited to announce my new book, The Essential Guide to Children's Clothing Sizes and How to Grade Them. This book explains children's clothing sizes in the United States, how they came about, and what sizes are used today. This book includes many things that have never been included in books on children's clothing design in the past.

  • A break down and explanation of children's clothing sizes from Preemie to size 16, including boys sizes.
  • A brief overview of difficulties in the industry, including obesity, and sleepwear
  • An explanation of how create your own grade rules.
  • Step-by-step instructions on how to grade basic styles, including grade rule charts.
  • Body measurement charts for infants to size 14, including slim and plus sizes for older children.
  • The infant measurement chart includes head circumference, neck circumference, hand length and width, foot length and width -- measurements that are hard to find.
  • Extra grade rule charts that include Newborn and size 9 months.
  • CAD grade rule charts
  • Complete measurement studies with additional body measurements, grade rules and references for infants, toddlers, 4-6x, girls (7-14), boys, and young men.
I will be doing a series over the coming weeks highlighting the above list with sneak peaks at what is in the book. This book is essential for anyone that designs and manufactures children's clothing. The book is currently available for purchase on Amazon or as an ebook on Payhip.

April 16, 2015

Grading from body measurements pt. 2

This is part two of an ongoing discussion about N. A. Schofield's article Pattern Grading found in the Sizing in Clothing book. Part one is here.

My initial reaction to the idea of grading from body measurements was, "Well, of course we should." And in fact, we do for children's clothing. It seemed rather obvious to me to look at children's clothing as a model. Children's sizing is based on the idea of growth, meaning that the measurement intervals between sizes are not always consistent.

Let's look at an example for a 4-6x size range.*

For sizes  4, 5, 6, 6x
Chest: 23, 24, 25, 25.5
Waist: 21.5, 22, 22.5, 23
Hip: 23.5, 24.5, 25.5, 26.5

The grade works out to be, choosing size 5 as the base size:
Chest: 1, 0, 1, 1.5
Waist: 0.5, 0, 0.5, 0.5
Hip: 1, 0, 1, 1

In this example, we have a 1" chest grade, except for size 6x which is 1.5". The waist is a 0.5" inch grade and the hip returns to a 1" grade for all sizes. Each body measurement area has it's own grade.

In women's clothing a 2" grade means that the interval change between the sizes will be 2" for chest, waist, and hips. Though even this isn't true across all brands, and you will find variations. (IMO, this is a good thing)

I don't know the history of women's sizing well enough to explain how this mode of practice came to be nor exactly why. It is clear that it does make grading, especially hand grading, much easier in practice. It is also unclear to me that grading is the source of our fitting woes. Nevertheless, it does make sense to me to go back and look at body measurements and devise a more precise grade rule.

The question then becomes, which body measurements do we use? In my children's example above, the numbers are still nice and easy to work with. The body measurements have been intentionally manipulated to be easy to work with. Raw measurement data was averaged, sorted, and studied to arrive at some numbers. Those numbers were not easy to work with, so a group of industry professionals sat down and made them that way. They modified certain measurements by about 1/8" to achieve consistency. Their modifications were rather minor and easily fall within a statistical margin of error. If you read their reasoning, it makes sense. This manipulation of measurement data for ease of use continues today in more modern measurement studies. It seems deceitful, but at the end of the day is infinitely practical. ASTM D4910 inherits this method of data handling from the measurement studies done in the 1940s, but does provide some updated measurements.

Looking at the Misses body measurement chart, ASTM D5585, it seems to be arranged and handled in the same way as the children's body measurement chart. IOW, the chart does not show a 1, 1.5, or 2 inch grade in the body measurements. It is a lot like the children's example above. There does seem to be a disconnect between measurement data and grading, at least on the surface. Individual companies will decide how to interpret and implement measurement data, and therefore their grade rules. (IMO, I think this is a good thing). And some will use a 2 inch grade, and some will not.

So what measurement data did Schofield use? She rejected the ASTM charts and created her own version of measurements derived from body measurement studies. This presented a problem because measurement studies do not always include the measurements needed for pattern making and grading. Schofield did not normalize the data, in other words make it easy to work with. Also she had to figure out how to deal with missing measurement data. I no longer have a copy of the article and can't look back, but Schofield selected certain measurements over others. How and why she handled those measurements puzzled me.

I believe Schofield's goal was to remove the idea of maintaining an ideal proportion or predictable pattern shape. She wanted to see what the body measurements really did between sizes.

Her results were almost predictable. More on that later.

*These measurements come from the withdrawn child measurement standard CS151-50. Measurements are in inches.

April 09, 2015

Grading from body measurements pt. 1

Pattern grading is the process by which new sizes are developed from an existing pattern. There are various methods or processes used to grade a pattern. These methods include slash-and-spread, shifting, and CAD. At the end of the day, each method accomplishes the same thing, a new size.

The apparel industry has received a lot of criticism for their sizing, especially of women's clothing. At it's core, sizing goes hand-in-hand with pattern grading. You have to define your sizes in order to grade a pattern. In order to grade a pattern you have to know body measurements for each size. The common grade rules for women's apparel is the 1", 1.5" and 2" grade rules used in the United States. Similar grade rules are found in Europe and the UK. The primary criticism is that these grade rules are not based on anthropometric data, or actual body measurements. Instead these grade rules are just pulled out of a hat without regard to women or their fitting needs. These arbitrary grade rules are merely for the convenience of industry.

This is the point of view taken by N. A. Schofield in her article Pattern Grading found in the Sizing in Clothing book. The goal of her research was to test the idea of creating grade rules based on actual body measurements rather than an arbitrary grade rule. There has been a lot of criticism of the industry over sizing and it is a worthy goal to research alternatives. Asking the why questions. Why does the apparel industry do things the way they do? Why do we grade women's clothing this way? Can we do it differently? I've asked a lot of these same questions as I've looked at children's clothing. When I started out, I didn't understand the why and sometimes the answer was not satisfying. I can totally get behind Schofield's motivation to try and find an answer.

And yet, I feel like I am setting up to be very critical of Schofield's research and I don't want to give the impression, as an industry professional, that even asking the questions were wrong. She was right to ask the question and to test an alternative. The results of her research are interesting and ironically (and indirectly) add support to current practices.

So here are some of Schofield's main arguments:

1. 1", 1.5", and 2" grade rules are not based on anthropometric data. Meaning it is not based on body measurements or the proportional relationships between body parts/areas. These grade rules were intended for the convenience and ease of hand grading.

2. Grade rules should be derived from body measurements. This means that grade breaks between bust, waist, and hips should not be consistent. Instead of a 34-36-38 chest measurement, we should be seeing a 34-35.5-38 (just as an example), chest measurement.

3. Size prediction and also body measurement prediction needs refinement. This idea is rather complex. Body measurement studies create a lot of raw data. In order to make sense of it, statisticians will test size prediction by using one or two body measurements. So can you predict the overall body size by using just the height or chest measurement? And if you do that, what influence does that have on other body measurements? If a person gets taller, do they also get wider? It is a complex question and not easily answered because there are so many variables. Statisticians bring order to raw measurement data so that we can organize the body measurements into sizes. They do this by averaging and, in some cases, normalizing the data so we can work with it easily. Schofield implies that we should just rely on the raw measurement data.

The ultimate goal of this study was to improve overall fit of women's apparel by basing grade rules on actual body measurements. I'll have to break up my review of this study into multiple blog entries because I have a lot to say about it. So stay tuned.

February 04, 2009

Who creates grade rules?

Tape measure

Some one asked me a grading question the other day. She wanted to know who creates grade rules?

A pattern maker, grader, or you could make the grade rules. If you choose to make the grade rules yourself, I have some guides available in The Organized Fashion Designer and The Simple Tech Pack. It's harder with children's clothing because there isn't as much standardization. An experienced grader should have some standard charts or be able to develop rules off of your measurement charts. I would personally start developing grade rules by referencing the Jack Handford book and make modifications as needed. I would only let a pattern maker or grader do it who has experience with it.

You can buy measurement charts from ASTM as a place to start. The ASTM measurement charts for children are probably the best resource for children's body measurements. Be cautious of using free charts found on the Internet. I have seen free measurement charts on the Internet riddled with inconsistencies that could lead to serious errors.

If you have time, you may want to sew up the smallest and largest sizes just to double check the grade and sizing. It doesn't have to be in your production fabric or anything. A fitting is the only way to know if your grade is correct. You won't need to do this on every style or very often. Kind of important when starting out though.