Math in Sewing [Pt 3]: Basic Bargello Quilting

My bargello quilting project...

Are you familiar with bargello quilting?

QuiltingDaily.com describes the bargello effect as "the appearance of movement within the patchwork, an optical illusion of waves flowing and ebbing that is created from the strip sets sewn together in an off-set, mathematical pattern."

Thus I welcome you to part three of my Math in Sewing series. Today I'll be demonstrating how to do some basic bargello quilting to make something rather unusual.

Sample quilt block...

If you search online for bargello quilting, you'll most likely read that it is deceptively easy to do, even though it looks complex. The illusion of complexity is derived from what appears to be small (typically square) pieces of fabric sewn together to form wavy patterns (and very often, colour gradients). In the photo here, if forty-five pieces of fabric actually had to be painstakingly joined together to form that block, you probably wouldn't be convinced that bargello quilting is easy.

In reality, after seven strips of fabric were sewn together first and then "sliced" in an appropriate fashion, the only sewing required to form this block was eight vertical seams.

By the way... long post warning!

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Background

This is a project that I started planning in mid-September and worked on for a couple of weeks. The sewing itself, however, was completed in a day and a half. The idea came from Liza Decor's YouTube channel, in a video uploaded on August 7, 2023. (The improv quilting technique that I featured here a couple of years ago was largely inspired by a video of hers.)

Start with seven strips of fabric...

While her video shows most of the process of sewing this up, she doesn't provide complete measurements. (To be fair, she uses the video to market the rulers that she sells and employs in this project.) This is why I took a couple of weeks to plan out the project, first creating a Word file for myself (so that I could refer to it without running the video repeatedly) and second, working out the missing measurements.

My different lengths of strips sewn together with a 1/4" seam allowance...

I made some guesses and used some math to come up with what I figured would be decently accurate measurements for this. (Oh, by the way, what "this" is, is a wavy table runner.)

Showing you how to cut the required panels using a small section of my pieced fabrics...

The video provides the information that the strips of fabric are 2" wide, with no indication given on length. Once I decided that the ruler she used looked to be 1" wide at the narrow end and 2" wide at the opposite end, I worked it out that the strips needed to be over 33" long... 36" would be ideal; WOF would be "safer" (More on that later.)

Alternate the orientation of the template across the pieced fabric...

She used up to nine different fabrics on her version of this table runner, but I wanted to keep things simple and went with just four. I chose a high contrast red for the center strip and binding, while three other neutrals did the job for the strips, the backing, and the "separator" panels (that's what I'm calling the non-pieced panels that are used between each pair of pieced panels).

NOTE: If you scroll back up to the third photo from the top, the numbers on the strips show you how to arrange three fabrics so that no two same squares end up beside each other after sewing.

Two adjacent pieced panels (one turned upside down) ready to be put right sides together and sewn...

All fabrics were Robert Kaufman selections that I've had for many, many years. (Originally from Craftsy.) I didn't think that I was that fond of the backing fabric, but after seeing the finished piece, the gold accents – which is featured on all of the selections – really tie everything together. The photos don't do the fabrics justice.

This is all four blocks joined together...

Speaking of photos, sorry for the poor lighting in some of these. It was a couple of very dark and dreary days when I was making this. I think the sun managed to make an appearance for only a couple of hours in the middle of the second afternoon. Then on the third day, it was extraordinarily sunny and I couldn't avoid the shadows.

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Preparation

If you're interested in trying this, you'll first need 7 strips of fabric measuring 2" x (at least) 36". The middle strip should be a high contrast to the others; i.e., if the other strips are light coloured, make the middle one dark or vice versa. Sew together with a 1/4" seam allowance and press all seams to one side.

Now measure the height of this resulting panel of fabric. Depending on how well you adhered to a 1/4" seam allowance, you should get a finished height somewhere in the neighbourhood of 10.5".

Showing how seams should be pressed...

Grab a piece of paper and draw a tall rectangle using whatever measurement you got as the height and 2" as the width. At the top edge of the rectangle, make a mark 1/2" in from each side. Draw lines from these marks all the way down to the respective bottom corners of the rectangle. Cut out this skinny angled shape – it should be 2" wide at one end and 1" wide at the other – and glue onto a piece of cardboard to make a template. Trace around it to make a second one. (Or better yet, if you have some sturdy plastic, use it to make a second template.) Put some double-sided tape on the back of the templates so that they will stay in place on the fabric.

[Why two templates? Having two helps you plan your cuts – to confirm that you have sufficient fabric, for example – since you can lay one down and move the second one to the other side, and so on.]

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The countdown is on: just 8 more regularly scheduled posts!

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I've shown in the previous pictures how the templates are used to cut the pieces required. (Just ignore the fact that my templates are longer than they needed to be.) You'll need twenty-two (22) pieced panels.

Here is another set of photos showing how the "separator" panels were cut.

Cutting the twelve "separator" pieces...

A 20" wide piece of fabric was folded in half for this. It was enough to accommodate the template going across it six times, yielding the required twelve (12) panels. I found that the best way to cut was to butt the edge of my ruler up against the edge of the plastic template, then take away the template and make the cut.

Make Blocks

The process to put this table runner together is really rather simple. Take two pieced panels, match them up right sides together and sew along one edge with a 1/4" seam allowance. Press both seams to one side. Do this with all twenty-two panels to create eleven connected pairs.

Three blocks plus one smaller block...

Then, take the separator panels and the pairs and lay them out as shown so you can make the required blocks. (Press the seams on the separator panels inwards.) If you lay out everything beforehand according to the photo above, you shouldn't have trouble keeping track of the correct orientation.

Once the four blocks (three consisting of three pairs and one with two pairs) are done, join them together and press the seams inwards again. If any outside edges are uneven, trim them up.

Apply Fusible Fleece & Backing

Lay the entire panel onto some fusible fleece (fusible side up), then pin, cut, and fuse.

Reinforced with fusible fleece...

Once cooled, lay the panel on top of the wrong side of whatever fabric you've chosen for the back and pin well. (If you happen to be a quilter and have some spray basting on hand, you may want to use it.) Unless you have large amounts of fabric around the perimeter, don't trim away the excess backing just yet.

Quilt

The next step is to do some quilting.

Adding a backing panel...

I chose to quilt lines along the inside edges of the separator panels. You definitely don't need to overdo it unless quilting is your passion.

Once the quilting is done, run a basting stitch along the entire perimeter.

All quilted and backing being trimmed...

Now you can trim back the excess fabric around the panel and give the whole thing a good press. (Having a hot iron at the ready is essential for this project.)

Bind & Finish

Next you'll need some 2" bias binding. I used this method on a 16" square of the red fabric and ended up with just a little bit more than I needed, so that was good.

The process of binding...

I didn't bother folding it and instead just used it as shown above; i.e., stitched it to the back side with a 1/2" seam allowance, then wrapped it around to the front, folded, pressed – an important step to make the final sewing so much easier – and sewn. (If you have a preferred method of attaching binding is, go with it.)

For neater corners, I bound each edge separately. I did the straight sides first. With the curvy edges, I left about a half inch at the ends to wrap the raw edge inside.

Bound and finished!

Once the binding is attached, give it good press all over and this bargello quilted wavy table runner is done!

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About the Math

Now let me tell you about a couple of "oopsies" that I made. You know how you're supposed to turn the template upside down to alternate the orientation of the pieced panels as you make the cuts across the fabric?

Well, for whatever reason, I got distracted early on and ended up making two identical cuts in a row!

Top side (doesn't the "dashed line" remind you of stitching?)...

The only way that I can even explain how that might have happened is due to my template – as you can see from the photos – being longer than what I needed. (That's because I made my templates before I sewed my fabric strips together, which was "oopsie" number one.) That being the case, the wider end of the template was beyond the edge of the fabric and I must not have noticed that it was at an odd angle when I made that second (identical) cut.

Examples of the "wonkiness" caused by my cutting mistake...

In any case, with my pieced fabric strips at about the exact length needed to accommodate the required twenty-two cuts, I didn't dare try to compensate for the mistake, in case I ended up short of fabric. So I just plowed on, knowing that the resulting pieces would be problematic to match up evenly. The sides being at the wrong angle means that the math part is off, which will affect the look of the finished item.

When I sewed together the pairs for the blocks, I did the best that I could to line up the red segments, but some of them just can't be made even, not without affecting the rest of the panel. Not only that, but each section is slightly tilted so that the implied "dashed line" is not smooth. In the end, I know that it's wonky (and why) but the result is still pleasing, so I'm not devastated. ◔ ⌣ ◔

Back side (finished dimensions about 34" x 10.25")...

One more observation relating to the math. Since I didn't use the entire length of my template, the widest edge of my pieced panels is less than 2". That being the case, the whole wave effect is reduced. If you go to the original YouTube video, you'll see that her table runner is definitely curvier than mine.

One potential use for my table topper...

Mathematically, if the widest part of the pieced panel is 2" or more, you'll get curvier results.

But now you have the basics to experiment. Use narrower or wider strips, use fewer strips, make fewer blocks (for a shorter topper) or make more blocks (for a longer topper). You have the tools and you now understand how math affects the outcome.

A Bonus Lesson Learned

Those who are truly knowledgeable about wedge rulers (and the math behind them) will have noticed that I made no mention of degrees. The fact is, I did not find out about the nature of these rulers until after I had finished this project and writing up this post. I decided against editing it too much and opted instead to extend this series.

After all, what better way to illustrate that knowledge of math can light the way to a solution, but that better knowledge of math can yield a better solution?

Therefore, stay tuned for yet another math-related post about DIY-ing a more accurate wedge ruler! I will then offer my own pattern for a similar bargello project that you can attempt, as a parting holiday gift from me. 😁

Before I go, just wanted to remind people that Spoonflower's annual November fat quarter sale is on until Monday night. It's been diminished somewhat, since for the first time, it's only 40% off, not 50%. (You can click through using the link at the top of the left sidebar.)

'Til next...