Before I made the sweater, I was a good knitter and made a gauge swatch. When knitting, the number of stitches per inch will determine your final measurements, so you do a gauge swatch of approximately four inches square (10cm x 10cm) to determine, and from a section in the middle of the swatch, count how many stitches there are in the four inches and divide by four to get an accurate stitches/inch. The bigger the item, the more important an accurate stitch count is. When making something which is 48" around (like the bust of a Fat Lady Sweater), the difference between 5 stitches/inch or 5.25 stitch/inch is a couple of extra inches.
(It mad math skillz like this that make me such a good engineer. Hah! People think that engineers must be So Good at Math, but civil engineers are not the math geniuses. C'mon, we work with geometry and concrete...just like the ancient Romans!)
I even washed the gauge swatch, and measured after it had dried. Lovely! That was a smart thing to do because after washing, my sweater actually measured the dimensions I'd calculated.
Except I didn't bother to check for the difference in length before and after washing my swatch. Most knitting patterns just say "knit until item is so many inches long". So I did.
Guess what. Not only does silk really stink when it's wet, it also stretches out in length. A lot. Even though the sweater was dried flat, it lengthened about 3 inches everywhere. The sleeves that once reached my knuckles? Now they hang way past the fingertips. And the low cut bosom? Let's just say the depth of that neckline wouldn't have looked out of place on the cover of one of those bodice ripper romance novels.