You know I've been buying vintage sewing patterns, right? I always have to adjust sewing patterns to fit me but these vintage patterns are almost never the right size even before adjustment. Most times, I can only find a pattern in one size anyways so I don't even try to find one that fits. Tha'ts because measurements were very different, back in the day; in particular, bust measurements were proportionally smaller than hip measurements (they're identical now) and waist measurements were proportionally bigger than they are now. Add to this the fact that every pattern company had different measurement systems and you can see how hard it would be to buy something vintage that came close to fitting.
So I end up having to grade the pattern pieces. Grading is easy if you already have at least two sizes of the same piece, because then you can just extend the pieces along the intersection points if you're only going up or down a size. Lately I've been working on that awesome bodice, and I'm having to grade it 8" up for my bust. That's a lot of change! I'm adding 2" to each of my bodice pieces and if I don't do it right, the design lines will be wrong.
The resource most vintage pattern-sellers point to is this one. It's not bad for one or two size grades. I tried its method with this pattern and then looked at what I had and said to myself, "how can I be increasing the bust by 8" and NOT be changing the length of the underarm seam?" I found a much better resource here - check out the quick reference guide! This one takes into account the fact that the length will change (and not just at the shoulder) and it grades at the shoulder as well.
Hopefully now I can get this stuff right. Yes, I know that in some ways it would be easier to take my measurements, draft a basic block including ease (I now know how to do that - and anyways, I know how much ease is included in this pattern), and do flat-pattern alterations to get what I want. But where's the fun in that? :)