Butterick 6183 top muslin part 2 - fitting the back

Fitting the back is hard and is not much fun when you have to do it on your own. It is so much easier to do the fitting on a dress form or someone else!
For now I have to rely on what I see in the pictures and make new pics after each adjustment to see if the fit is improved.

fitting 1
This is the size 10 muslin:


- At first sight you see a snug fit, no ease at the upper back. I already determined that my muslin is a size too small, but the length seems to be good (placing of the apex and waist markings are good)
- There are diagonal wrinkles towards the shoulder - I guess sizing up will sold this problem due to more ease across shoulder blades. If it was a sleeveless top I'd do a forward shoulder adjustment as well, but for a top with sleeves I think it is not necessary.
- Looking at the pictures, what's more interesting is the waistline. There are horizontal fold wrinkles at the waistline. What you also see (especially from the side) is that the back hem is raised. Fold wrinkles means there is excess fabric. At first sight you'd think it is a swayback problem, right? But: this could be a sign of a too tight fit across the hips. Probably the combination of both.
To check this I decided to open up the back seams from the waistline down.

fitting 2.


- The back looks much more relaxed with the seams open and wrinkles are gone! More room in the hips is definitely part of the wrinkle-problem. It would be easier to deal with this if the finished measurements were printed somewhere on the envelope or the pattern pieces...now I have no idea how much ease is built in...
- I marked the waistline and another thing I notice is that the waistline marking (black line at the back) is sloping downwards. (note: the line at the front is not the waistline but the lengthen/shorten line of the pattern):


The waistline needs to be 'lifted', which means that my back waist length is shorter than the pattern's. This is a swayback adjustment.You can see here that the side seam is pretty much vertical, so I only need to add width at the back.


fitting 3.
alterations done:
- Pinched out 1 cm at the center back for swayback adjustment, tapered to nothing at the side panels
- closed the side seams, added 1x seam allowance at both seams


- the fit at the hemline seems to be fine now, even when wearing a jeans underneath
- the waistline sits at the right place and looks horizontal:


I'm happy with how the top looks now and not going to make another muslin. I'm going to transfer all the adjustments to the pattern pieces.

pattern adjustments to do:
- add 3 cm length at hemline
- alter sleevecap by adding width (2x1cm)
- cut size larger pattern pieces (probably need to shorten the bodice pieces a tad to keep placing the waistline at the same height)
- add width at the hips in the back (3 cm at hemline tapering to nothing at waistline)
- do a minimal swayback adjustment (raise waistline by 1 cm)