Welcome back - we're going to be drafting the back sloper now.
If you've just joined us, this will probably make more sense if you first read the Overview post and the Front Sloper post, both of which explain the terms we'll be using, the colors of lines and dots and the purpose of the hideous pink arrows. You will also find a Measuring Table worksheet in the Overview post that you can print out and fill out as you take measurements.
Drafting the back sloper is the same as the front, with the following differences:
- The back neckline is higher
- The back armscye is shallower (less curvy)
- There is a back dart to reduce the fullness of the fabric in the back waist region
- In addition to the Shoulder Point and the Side/Base of Neck points that we introduced in the Front Sloper post, we will also need to ascertain the position of the Back of Neck point:
To locate it, have the child tip his/her head forward so his/chin touches his/her chest. Feel on the back of the neck for the most prominent bone (first thoracic vertebra? Last cervical vertebra? I can never remember) at the top of the spinal column. In a garment, this position will be the bottom of a snugly-fitting shirt collar (or a mandarin collar). Mark it with a sticker or a marker.
Let's get started! Remember now that all the measurements will be taken on/along the back of the child.
Draw the vertical Center Back line along the left side of the paper.
Draw the horizontal Shoulder Line along the top of the paper.
Measure the vertical distance (#19) between the Side/Base of Neck point to the Waist. It may not be the same as the corresponding measurement in the front (#1).
Draw a horizontal line this distance below the Shoulder Line. This is the Waist Line. Mine was 10.5".
Measure the vertical distance (#20) between the Waist and the Back of Neck point. This is measured along the Center Back line of the body.
On the Center Back Line of your draft, mark a point this distance upwards from the Waist (pink arrow). Mine was 9.5".
Measure the horizontal distance (#21) between the two Shoulder Points. This measurement spans both halves of the body, so we will divide the measurement by two to get the half value.
Plot this half-distance from the Center Back Line (see pink arrow direction) and along the Shoulder Line, and mark the point.
My Shoulder Width was 10" and the half value was 5".
Q: Um, you know, some drafting resources recommend that you measure this distance sort of arched across the back of the neck, instead of purely horizontally across like you did. Who's right?
A: Like this, you mean? The way my mother does? Also the way I measure my husband's shoulders to decide whether or not a store-bought shirt will fit him?
(Meandering discussion about to take place here):
Both work. It depends on what you'll do with the measurement. The real old tailors and other old-school types often use the arched-across-the-back-of-neck method. I learnt it that way also. Mum says it gives a better fit. She's right, but only because of how she uses that measurement in her draft.
First, I must mention that the back of the shoulders is quite different from the front. There are muscles and bones in the back shoulder area that make that whole region more curved than the flatter front shoulders. If you have the chance to enjoy a bird's eye view of a person's head and shoulders, you'll appreciate this observation even more. For that reason, sometimes the back shoulder width is greater than the front, and even more so if that person has a rounded back or hunched shoulders or a similar anatomical gift. In such cases, we might even add a shoulder dart on each side of the shoulder seam to help shape the fabric around the roundedness. And to plot that dart, we measure the horizontal straight-across shoulder width (#21) as well as the arched-over-the-back-of-neck shoulder width that my mother uses and use the difference in those values to make the dart. But I imagine that we would hardly need that for the vast majority of children's slopers.
Second, I will say that I use both measurements - the arched one usually as a check. We will use the straight-across measurement here because it is easier to visualize and more straightforward. And it is the same method as we used for the front.
Measure the horizontal distance (#22) between the Side/Base of Neck and the Shoulder Point.
On the Shoulder Line of your draft, plot this distance backwards/leftwards from the Shoulder Point you plotted in Step 4, as shown by the direction of the pink arrow. Mark this point - it is the position of the Side/Base of Neck on your draft. Mine was 2 5/8".
Here we will pause to do a check.
Measure around the back of the neck between the two Side/Base of Neck points as shown in the sketch (#23). Unlike the front Width of Neck (#5) measurement, this is not a straight-across one - it curves around the neck and passes through the Back of Neck point. As a result, it is a (slightly) greater value than the front Width of Neck.
Divide this by two (because it spans both halves of the body) and check this half-value against your draft as shown. My width of neck (back) was 4 3/4" and the half value was 2 3/8".
Now we will draw the Back Neckline between the Base of Neck point and the Back of Neck point, as shown by the two pink arrows.
Measure the vertical distance (#24) between the Waist and the Shoulder Point. On your draft, plot this distance upwards from the Waist Line, and mark the end point so that it is directly under the mark you plotted in Step 4 (pink arrow).
This new mark is the Shoulder Point. Mine was 8 7/8".
Here we will do another check, just like with the front sloper.
Measure the diagonal distance (#25) between the Shoulder Point you plotted in Step 8, and Waist Center Back point (the intersection point of the Waist Line and the Center Back Line).
Check it against your draft - it should be the same (or very close). Mine was 10 1/8".
Draw the Shoulder Slope - a straight line between the Side/Base of Neck point and the Shoulder Point.
We're now going to add in the Chest measurement.
Measure the vertical distance (#27) between the Side/Base of Neck point and the Chest, the same way you did in Step 12 of the Front Sloper.
Add 1"of ease to that (just like with the Front Sloper) and draw a horizontal line on your draft that is this distance below the Shoulder Line.
This is the Chest Line.
Use the same chest measurement (#26 = #9) that you used with the Front Sloper and plot the quarter measurement from the Center Back Line, along the Chest Line, marking the end point.
We're now going to add in the Waist measurement.
Obtain the measurement of the back of the Waist (#28). This can be done two ways:
(i) Measure horizontally from one (imaginary) side seam to the other, around the back of the Waist, adding a little comfortable fitting ease.
(ii) Subtract #12 from #13.
Plot this distance from the Center Back Line, along the Waist Line and mark the end point.
We're now going to add in the Hip measurement.
Obtain the vertical Hip Level measurement that is between the Waist and Hip. This is the same as #16.
Draw a horizontal line this distance below the Waist Line on your draft.
This is the Hip Line.
Obtain the back Hip measurement (#29). This can be done two ways:
(i) Measure horizontally from one (imaginary) side seam to the other, around the back of the Hip, adding a little comfortable fitting ease.
(ii) Subtract #14 from #15.
Plot this distance from the Center Back Line, along the Hip Line and mark the end point.
Before we draw the side seam lines from armpit to hip, we need to add a back dart.
Q: Why? You didn't add a dart in the front sloper!
A: That's because it was for a child with no fullness (e.g. bust) in the front. If it were for a mature adult female there would be at least one dart in the front sloper. In the back sloper, however, children and women (and men, if they were willing to wear sheath dresses!) alike have a hollow in their backs that require a dart.
First, we will locate the position of the upper point of the dart. For the back, this is strongly related to the shoulder blades. Often, people conveniently plot this along the Chest Line. That is a good rule of thumb, but I thought I'd explain the rationale a bit by starting with the shoulder blades.
A: Because the shoulder blades are the sticky-out-est part of the back. This means that immediately below and around them are the hollowest part of the back. And a correctly positioned dart is one that reduces the fullness in the hollowest part of the body.
So anyway, locate the shoulder blades of the child when he/she is standing at rest. Measure the distance between their edges (#30). This spans both halves of the body so again we will need the half-value. Mine was 4 1/4" and the half value was 2 1/8". Then measure the vertical distance (#31) between the Waist and this level of the shoulder blades. Mine was 5.5".
Plot this point so that it is
- A horizontal distance of (half of #30) from the Center Back Line (first pink arrow) and
- A vertical distance of #31 upwards from the Waist Line (second pink arrow).
Now often when we plot dart points, we have them start a little way below, and end a little way above the actual start and end points. This gives a more gradual and smoother dart that wraps around the pointy bits of the body without themselves being pointy.
So let's lower the upper dart point by 1" which is, again, a rule of thumb.
Now our actual upper dart point is the one in blue. Which brings the point pretty darn close to the Chest Line, which we talked about in Step 16, which brings us full circle!. Except now we know why this dart is plotted with its upper point there.
Now comes the easy part.
Draw a vertical line from this upper dart point all the way to the Hip Line.
This is the center line of the dart.
Q: Why stop at the Hip Line?
A: The Hip is the biggest/fullest part of the lower body. Remember we said that darts reduce fullness at the hollowest parts of the body? The hollowest part of the back body lies between the shoulder blades and the buttocks/hip. The dart doesn't need to go below that.
Measure along the Waist Line of your draft, half an inch to either side of that center dart line. These will be the side points of the dart.
Q: Why 1/2"? Where did that 1/2" come from?
A: Experience, and a convenient rule of thumb. Most people's backs are nicely darted with this size dart. But you will know for sure if it's the right size for you when you've made the muslin. Till then, this is a good starting point.
Draw two straight lines from the upper dart point to these two side dart points:
Using the same rationale as in Step 17, we will raise the lower dart point by 1".
Complete the lower half of the dart by joining the side dart points to this lower dart point.
Now in making a dart, we are taking in some fullness at the Waist. This means when we sew the dart in the garment, the Waist gets smaller by the width of the dart (1" in our case). This means the Waist is now too tight by 1". We need to add this dart width (i.e. the 1") to the side seam to bring the Waist back to its original pre-dart width.
Mark a point 1" (width of our dart) to the right of the original (red) Waist point. This is the black point indicated by the pink arrow.
Now let's draw in the side seams!
One straight line from the Chest to the Waist and another straight line from the Waist to the Hip, going through all those pink-arrowed end points.
Drop a vertical line from the Hip (the biggest part of the lower back body) to form the rest of the side seam.
Obtain the position of the hemline(s).
Use the Waist-to-Knee distance (#17) and/or the Waist-to-Ankle distance (#18) from the Front Sloper and draw in the horizontal Hem Lines.
Remember to curve the Hem Lines up slightly at the side seam, and go over all the actual sewing/fold lines of the sloper in black so you know where to cut:
Draw in the back armscye (in bright red below), either with a free-hand sketch or using the round-down method (with the flexible curve) in Step 20 of the Front Sloper post.
Here are the front and back slopers side by side so you can see the difference in shape of the two armscyes. The back is shallower (more vertical) than the front.
And here are the front and back slopers juxtaposed: Notice that all the horizontal green lines match up (or are at least very close) i.e. the front Waist Line is at the same level as the back Waist Line etc.
And now, cut out the slopers and do a final check for overall fit in the next post!