I have previously blogged about Jack Handford's book Professional Pattern Grading (I like this grading book!). I just graded my basic infant bodices using Handford's grading charts and I just wanted to pass on a few insights.
If you read my blog on children's sizing (Too Many Sizes!), then you will know that there is a lot of variety in how manufacturer's lay out their size ranges. Handford is not really any different. His sizing breaks down like this:
3M, 6M, 12M, 18M, 24M, 36M
You will notice that the 9M size is missing. A 9M is considered a half size between 6M and 12M. Some manufacturers include it and others skip it. After studying dozens of measurement charts, I tend to favor skipping it. Children grow really fast in the first few months of life, so there is no need to include lots of possible sizes.
Another thing to consider is his 24m and 36M sizes. His toddler sizes break down like this:
1, 2, 3, 4
Except for boutique/specialty shop stores, you don't really see toddler sizes denoted like this. Normally, the toddler range is 2T, 3T, and 4T (some throw in a 5T). Anyway, there may be some overlap between the infant and toddler sizes with your patterns. This doesn't mean you can grade all of the infant and toddler sizes together. You will still need an infant block and a toddler block. You may have some shaping differences between the two.
It took me some time to wrap my brain around his grading instructions. I could look at the diagrams and see that this was the type of grading done in the industry. Even computer grading takes it's cues from this method. The actual grading process, however, varies from computerized grading.
I am accustomed to working with all of the pieces nested together. I can select a grading point and enter in the X,Y changes. It really is pretty simple. Handford has you grade one size at a time. After grading one size, you cut it out and use it to grade the next size. Precision is absolutely key because mistakes gradually increase with each size. I eventually got the hang of it and found it to be pretty easy. Once I had all of the sizes, I nested them on top of each other and I could see how well it worked. And it did work well.
So now I have two sets of infant bodice patterns using the Handford method and an adaptation of Aldrich's measurement charts. I am going to compare the two to see which I like better. So far, there doesn't seem to be too much disagreement between them. I am also trying to decide if I should add in a 9M. Right now, I am leaning toward Handford.