January 11, 2007

Sizing Studies for Children

A few weeks ago, a new mother complained about the variation in infant clothing sizes. She explained that her 12 month daughter wore clothes ranging in size from 6m to 18m. Some marked for 12 months were either too big or too small. Finding clothes that fit was a matter of trying things on a fussy baby.

She stated, "You can't trust what the size tag says."

Kathleen at Fashion-Incubator wrote an article about problems with sizing studies, especially for women. Children's sizing studies present some of the same difficulties. Children's sizing is complicated by the fact that children grow and at different rates. Ethnicity plays a part in proportions, weight, and growth rates. As a technical designer, I feel that I am only taking my best guess when drafting patterns. I have to synthesize about a dozen different size charts and methods to come up with something that works and fits! I firmly believe that even infant children deserve clothing that fits.

My concern with most measurement charts and sizing studies are that they are minimally useful for patternmaking for infants. Many measurement size charts either completely ignore or present limited info for infant sizing. The Armstrong book starts her charts at size 2/2T (some of her measurements are a bit funky too). The Gloria Mortimer-Dunn book is the same way. Childrenswear Design, has some basic information for infant patternmaking although the information is not complete. The best presentation of measurement info is from Winifred Aldrich in her book Metric Pattern Cutting for Children's Wear and Babywear: From Birth to 14 Years .

I have drafted basic blocks using Aldrich's charts and instructions. They turned out ok, but definitely needed refinement for style and fit. I thought the basic, fitted blocks need a little more ease and a lower neck. The flat blocks needed a better armhole shaping. Despite that, with some tweaking, you could have a nice set of infant blocks to work with. Part of my difficulty could be that the British are accustomed to a closer fitting block and the metric system. I had to wrap my head around metric conversions, which probably introduced some inaccuracies.

I haven't talked much about measurement charts available from ASTM. This is because I have not purchased a set of charts from them. I don't have the need at this point. Other government studies are interesting, but don't contain enough of the measurements needed to draft basic blocks. Growth charts and retail size charts (and a few in patternmaking books), list infant sizes by pounds and lengths. Those are interesting for comparison and not useful for drafting patterns.

I am not sure what new childrenswear designers are to do. Most companies develop their own measurement charts and some are better than others. Getting those first, good bodice block patterns are critical because every future design is based off of them. It may be easier to drape your first blocks off of dress forms rather than drafting from measurements. Or maybe a combination of both. This sizing study problem could explain why infant sizing is all over the place.

Over the years, I have settled with basic patterns that have proven to work. They continue to be modified for improvement and someday they will be what I hope is a great pattern.

Disappearing Ink Pens for the Sewing Room

These disappearing ink pens are among my favorite tools. I go through several of them every year. I use them to trace around a pattern directly on to fabric for cutting. I also use them to mark stitching lines like darts, fly-fronts, or even quilting lines. It is great for marking match points in the middle of a piece. I rarely make tailor tacks or sew-baste thread markings.

In this picture, you can see how well the line shows up, even on difficult to mark fabrics like blue. This drawn line came from a pen that is nearly dead (I use them until they are dead). It works on most light to medium colored fabrics. It has difficulty with anything that is pink, red and of course black. For those colors I whip out chalk pencils or soap remnants (soap usually works better). I have used these pens on a variety of fabrics from silks, satins, laces, flannels, broacloths, to denims. I use them on personal projects and in industry settings.

The back of the package says to test on fabrics before using. I have had very few problems with the ink not disappearing. If I were to topstitch a fly, I may test it. The last pair of pants I made, the fabric had a finish on it that prevented some of the ink from disappearing. But it all came out in the wash. I wouldn't iron over the ink until it has completely disappeared - the heat/steam from the iron may set it. It would be rare for the ink to become permanent. Most of my ink lines are from tracing around pattern pieces, so they would never be seen anyway. The package states the ink disappears within 24-72 hours. I find it disappears much faster than that, especially when exposed to air. The age of the pen also determines how long the mark will last.

I have difficulty finding this exact pen in the fabric stores. They carry disappearing ink pens, but they don't work as well. For some strange reason fabric stores (the ones near me) carry Dritz marking pens, but not this one. This pen is from Dritz and I can be ordered from Amazon.

January 08, 2007

Points of Measure and Grading

In a previous grading blog, I showed the first step in developing grade rules. I usually break my measurement and grading charts into two charts. Here is an example:

An example of developing a grade rule

I usually stop at the middle chart and work the rest of the math out in my head as I grade. Some of you may want to break your measurements down even further. If a pattern piece is symmetrical, you can grade half of the pattern at a time. The third chart shows the grades for half of the pattern width.

My charts have a column on the left titled POM, or point of measure. Those points of measure should correspond to a drawing like this:

Points of measure on a pattern piece

The measurements in the top chart above are based off pattern measurements (which are made up for this example), rather than body measurement charts. The grades are developed from body measurements. To grade successfully, you will need to take a lot of measurements off your base size patterns. For a bodice pattern, you will need armhole circumference, across the shoulder neck circumference, neck width, neck depth, and possibly more. Work between your body measurements, pattern measurements, grade, and ease requirements to develop appropriate grade rules for each point of measure. BTW, if your pattern measurements are finished measurements (minus seam allowances), you can use these charts to measure finished garments while doing quality assessments.

There are standard reference grading charts available from various sources. You can refer to them to develop your grade rules, if you like, and it may save you some time. Standard grading charts are usually available for adult, most often, women's clothing. Children's grading charts are available, but I have found them less useful. There are too many variations in children's body measurements, and every company has their own set. I usually have to develop grading charts that are unique for each company. When a designer asks me to grade a pattern, I have to work off of their measurement charts and basic pattern pieces for the grade to make sense. I will compare their measurement charts with my own to make sure their measurement and grades fall within an acceptable range.

If you do use a standard reference grading chart, you will need to double check your pattern/body measurements across the range. Standard grade charts do not accommodate variations in body type that your company may try to fit.

In the next grading blog, I will begin to explain the actual process of grading.

January 02, 2007

Knits-Wovens - How to tame the stretch


Remember my previous blog on flower buttons? I promised to blog further on how this manufacturer worked with combining knits and wovens. Combining knits and wovens opens up wonderful design opportunities, that is until you try to sew the two together. The knits invariably stretch out of shape and the wovens will stubbornly refuse to stretch.

The most frustrating thing is trying to gather a skirt (with a high gather ratio) to a knit bodice. Imagine a pretty gathered taffeta skirt sewn to a stretch velvet top. While I am not going to explain every tip and trick out there, this well-loved jacket has some excellent examples of how to do this.

The most important thing to remember when combining the two is that knits will have to be stabilized in some way. This jacket has a facing which has been interfaced with a light-weight interfacing appropriate for a stretch fabric. In other words, after the interfacing is applied, the knit fabric retains some of its knit characteristics - it doesn't feel stiff as a board. The interfacing prevents the buttonholes from stretching out and the topstitching is straight and even.

As a design inspiration, you can see how the facing is an entirely different fabric. The neckline and center front seams would have been too bulky if faced with the french terry knit. Instead, they used a flower print jersey. I am sure this jacket was part of a two piece set that had a matching pair of flower print pants.

The gathered eyelet trim was pre-gathered onto a twill tape and then applied to the hem. The manufacturer could have applied a twill tape to the jacket and then gathered the trim directly to the hem. In either case, the knit fabric has to be stabilized to prevent stretching. The jacket, sleeve and pocket hems all have this gathered eyelet trim. Wow!

The manufacturer gets bonus points for their patch pocket application. The rounded pocket would have been very difficult to maintain the round shape and topstitch it without stretching. They used a 1/2" strip of interfacing around the edge of the pocket. This picture is a close-up of the inside of the pocket.

The final tip is not easily observable. In a factory, the sewing machines can be adjusted to help prevent stretching. How the fabric is fed through the machine is part of the reason store-bought knits look so good. This adjustment is often called the differential and it refers to the movement of the feed dogs. Industrial machines with differential feed have two sets of feed dogs. These feed dogs can be adjusted in how far they move back and forth and up and down, in relation to each other. The front feed dogs can either pull extra fabric or pull less in relation to the back feed. This is not to be confused with the stitch length, also controlled by the feed dogs. Few home machines, with the exception of some overlock sergers, have this ability, requiring knits to be stabilized even more when sewn. A walking-foot attachment, or machine, may help with seam distortion too. American and Efird has some good suggestions on sewing knits.

Country of origin labeling for clothing


I couldn't resist writing a blog about this particular care/content tag found in a t-shirt that was a Christmas present. This is perhaps one of the worst labels I have seen in a long time. In fact, I believe it was purposely written to make it look like it was made in the USA.

The maker of this shirt did a few things right. The tag clearly states the content of 100% Cotton and it was placed at the back of the neck. Unfortunately, this is the only thing they did right.

The first obvious problem is the different font sizes. Notice how the words Dominican Republic are smaller than anything else. You might think they made those words smaller so they could fit on one line of the tag. But the placement of all the words could make a consumer believe the shirt was actually made in the USA. I did when I first looked at it. Further, the addition of the phrase "of USA Fabric" is extraneous. It should simply state, "Made in Dominican Republic" period.

This tag would not be acceptable by FTC guidelines. When writing a tag, all of the words on the tag should be of a uniform, legible font size. The tag would be rejected for more than the font size issue. This particular shirt is missing a care tag and manufacturer identification. The content tag does not need to include the manufacturers name or RN number. That information should be included on the care tag and/or other packaging. It would be impossible to track down who manufactured this shirt. The FTC could go after the retailer, in this case.

This kind of thing should have been caught when the items were brought into the US. I am, however, not surprised to see it was missed.