Grading up vintage patterns: proportion and preservation

It's beautiful! It's everything I want in a dress! It's a vintage 16 and I am...

bigger.

Tanya on Curvy Sewing Collective just covered the basics in a very clear tutorial

photo from Curvy Collective, Tanya http://tanyamaile.com/

But what about smaller pieces with darts and seams and connections to other pieces?

Let's say, a bodice with an angled collar. Like Mail Order 9213

I am going to trace the original pattern piece and cut that piece up, preserving the first one. I can trace and shift, but I get lost and forget where I've traced and shifted, and slicing the pieces gives me a chance to play around with proportions. And I've covered myself in the very likely event I make a hash of it.

The green lines are the ones I can mess with and no real design change will occur. The Red is super caution and the yellow needs thinking about.

The blue lines are sort of a standard bodice slice. Through the bust point vertically and horizontally, at the front edge and through the armsceye. I never want to add all the width at one point. Ever. It will look awful.

I measured myself vs the pattern's size measurements. I am assuming the pattern takes wearing ease into account, and won't get into the precise nitty gritty of fitting ME and MY SPECIAL ISSUES until later.

I need two inches all the way around, checking by my waist and upper bust #s. So, one inch in the whole front bodice; I want to add a half inch to each side of the front.

What I want is to keep the high angle of the collar. I don't want it floating as a little collar in a sea of bodice (which will happen if I just add width through the shoulder seam), and I don't want it suuuuper wide on either sloping angle. So I want to add a little here and a little there.

It is easier to manage adding the width first. Adding the same width to each cut keeps it even. So if I'm adding half an inch to this piece, each cut is 1/4 inch wide to keep things about the same. I tack this down with a little tape (usually there are strips of tracing paper flying around the table for backing purposes) .

Don't draw lines yet.

This is where you can play a little. I don't need adjusting in the armsceye, but I do need a little in the bodice below the bust point (usually I need to shorten this part).  I am NOT doing a bust adjustment in this manuever. I would lengthen by 1/4", but if you know you are a long torso from previous experience, measure yourself and do that deed NOW below the bust point.

If I think the collar has just gotten too small, I can grab it and move it. If I want it smaller, I can cut that section up and move the pieces around WITHIN the boundaries of how big the bodice needs to be.

(this is why I make the copy. I like to play with my toys!)

Redraw lines. The shoulder seam got a little longer, the collar a little longer and deeper.

 Time for one more think over on the v neck collar. I'm going to cheat it down a little in the center. I am a modest gal, but I like the sharp angle at center.

You will, eventually, retrace this on new paper. Move the marks (seam marks, bust point, original darts) to where they should be on the new piece. You should mark the bust point by trying this piece on you. That's when the bust adjustment happens (that is, I don't have one)

Keep in mind that if you add height to any seam, the other piece of that seam (a sleeve, a back bodice) will need to be adjusted similarly. This is where it works to do these pieces at the same time.

On a big table

I did the slide method for the skirt until I realized the waist yoke pieces were getting lost in my wiiiiiiiide new front piece. So there're a whole set of frankenpattern photos that follow this one. I'll just keep that to myself.

It is easier to make mistakes on paper than fabric. You will make a few truly huge boneheaded errors, from which you will become brilliant.