So, in both methods you sew your enclosed shapes (I tend to call them worms so if I slip and say that, know that it means enclosed shape.) I personally like to sew right up to the stitching at the beginning and tie threads off at the back rather than backstitch each end. So my stitching would very simply look like this.
At this point, in traditional trapunto, you slit the back of the fabric between the lines of stitching and fill with cotton or some kind of stuffing.
Then stitch it up. So the back of your piece has cut fabric and stitching down the middle of each worm. Besides being a difficult technique, it also leaves the fabric susceptible to fraying and looks very messy.
For worms that turn sharply you enter one end of the tunnel, come up at the turn, pull yarn through, and then go back in same hole and finish end of worm. Once you’ve done this the back of the fabric will look more like this.
Now I’d like to talk about your choice of fabrics for the front side of the trapunto and the back side. The front can be anything you like AS LONG AS YOU WASH IT FIRST or otherwise clean as you would the finished product. I have dogs so everything in my house has to be either machine washable or leather. I picked 100% linen since I was aiming for a look that was medieval and linen was available during the middle ages. Also, the linen I chose didn’t shrink at all when it was washed. I chose a “Utility” fabric (Yes, it said Utility Fabric on the bolt at Joann’s Fabric and Craft store. I cut a small test piece, serged the edges and washed and dried it. It shrunk about a third it’s length and width – PERFECT. I like the combination of fabric that doesn’t shrink with the backer that does because once you’ve done the actual stuffing and wet it, the backer shrinks and pushes the front out.
Typical trapunto made with the front fabric and backer made with similar shrinkage fabrics will look like this when viewed on edge.
If you use a backer that initially shrinks a lot more than the front fabric you’ll get more relief on the front. The cross section view will look more like this.
But this does create a bit of pucker between sections of the worms and some backer will need to be cut away or at least slit so the pucker doesn’t detract from the overall look.
On the front I did a bit of tea dying in an unusual way. I sprinkled loose tea on the design, brushing it into the corners and off the raised areas, and misted it with hot water. After I rinsed this out and let it dry I also dry-brushed (using a toothbrush) brown shoe polish (the old-style paste shoe polish) into the edges. I discovered a long time ago that shoe polish stains so I use it quite a bit for antiquing. So, design done, I added piping and an envelope closure back. Very easy project and I hope you have fun trying either this design or another one that lends itself to trapunto.