A couple of years ago I started working with princess line shaping, using it for many of the designs in Lace Knits. I love it! It produces a particularly elegant look, a tailored chic, and it is very simple to calculate. Win!
I haven’t yet published any digital patterns that feature princess line shaping, though one is coming very soon. Meanwhile I’ll explain it with pictures from Lace Knits. It is particularly evident in the Lindley camisole:
My sweaters are all designed for seamless knitting, but the shaping is calculated as though front and back are separate pieces of equal width. Divide the full circumference in two, half the stitches for the front, and half the stitches for the back. Then proceed as follows to place the princess line shaping.
Aim to have one half of the stitches between the princess lines at the centre front, and one quarter of the stitches to the left of this, and the remaining quarter of the stitches to the right of this.
To do this as nearly as possible divide the front stitch count by 4, ie into quarters. For stitch counts that are not a multiple of 4 round down to the nearest multiple of 4. For example if you have 155 stitches in the front, round down to 152, then divide by 4. In this example a rounded quarter of the stitch count is 38 stitches. We have 3 stitches remaining (155 – 152 = 3). Divide these 3 stitches between the 3 front portions, so that you place 39 stitches to the left, 39 stitches to the right, and 77 stitches to the centre front. If your remainder is 2 stitches divide these between the side quarters. If your remainder is 1 stitch add this to the centre front.
Aim to have a third of the stitches at the centre back, a third of the stitches at back left, and a third of the stitches at back right.
To do this as nearly as possible divide the back stitch count by 3, ie into thirds. For stitch counts that are not a multiple of 3 round down to the nearest multiple of 3. For example if you have 155 stitches in the back, round down to 153, then divide by 3. In this example a rounded third of the stitch count is 51 stitches. We have 2 stitches remaining (155 – 153 = 2). Add these stitches to the side portions, so that you place 52 stitches to the left, 52 stitches to the right, and 51 stitches to the centre back. If your remainder is 1 stitch add this to the centre back.
Once you have the numbers calculated for front and back, you can calculate how many stitches are around the side by adding together the stitches from one front side portion and the stitches from the adjacent back side portion. In my example 39 + 52 = 91. Now we have all the information required for placing princess line markers:
Set-up round: k39 (front proper* left), place marker, k77 (centre front), place marker, k91 (proper right side), place marker, k51 (centre back), k52 (back proper left).
Maintain the relative proportions of the different shaping areas throughout the princess line shaping. To do this place shaping stitches in pairs at every shaping point, one at each side of the marker. When working a decrease round work a decrease immediately before and immediately after each shaping marker. When working an increase round, work an increase 1 stitch before and 1 stitch after each shaping marker. This means there are 8 shaping stitches in each shaping round. That’s double the amount of shaping stitches in standard shaping schemes, so the shaping needs spacing out to double the distance between shaping rounds compared to standard shaping schemes. In the top-down Lindley camisole with 9.5 rounds per inch, the chest to waist decreases occur in every 16th round, and the waist to hip increases occur every 10th round.
*Left and right are confusing terms unless we know the context. ‘Proper’ indicates the wearer’s own left or right. So ‘proper left’ means what would be on my left from my point of view if I were wearing the garment.