After a little over a year and a half, and many interruptions, we finally finished our embroidermated short, Chad Gadya. While we were working on it (actually I was working, Theo was procrastinating) this other embroidered short came out, but there are differences. Thanks to Theodore Gray’s stitchcoding in Mathematica, we weren’t restricted by (invariably crappy) off-the-shelf software. This allowed us to automate beautiful iridescent stitches and preserve them from frame to frame, so the resulting animation really looks like moving embroidery.
“It took a while to get all this code right, but of course it’s crucial that it cover every possible case, because when you’re doing animation, it’s not about getting one frame right, it’s about having an automated process that always gets every frame right, not just once, but every time there is an iteration of the animation requiring a re-render of the frames. We must have generated tens of thousands of frames (just generated the files, not actually stitched them!) before it was all looking good.” Theodore Gray
Welcome to my new Stitching Blog. It’s like my regular blog except all about quilting and embroidery. I’ve separated the two, because I get the feeling that people interesting in my science writing and app-making activities may find all the stitching a bit tedious, and vise-versa. Also, I have taken the liberty of using the same list of subscribers to my stitchcam as the list to be notified (via rss feed) when there’s a new post on this blog. I figure if you’re interested enough in stitching to get real-time notifications of a quilting machine running, you’re probably interested enough to hear about an occasional blog post.
So without further ado, my first new stitching-related blog post. I’m afraid it’s a rather technical one….
One of the big problems with fabrics and quilting is that fabric is not a proper engineering material. It’s stretchy and sloppy and never goes exactly where you want it to. The situation only gets worse when you add batting to the equation.
We’ve been experimenting with extra-thick batting, as much as two inches thick, and have had a problem with the resulting “quilts” not lying flat, because some parts of the pattern shrink the dimensions of the fabric more than other parts, resulting in a sheet that is internally stressed.
You might think it’s a simple case of more stitches equals more shrinkage (as it more or less is with embroidery), but this is not the case.
To see why, consider a cross section of a quilt with different spacings between the quilting lines. When there are no lines, the fabric on the top and bottom are flat, and the piece overall will be just as long as the fabric originally was. As you add more lines, the fabric is forced to go up and down, so even if the fabric isn’t physically compressed, the piece overall will get shorter.
Here is a schematic illustrating this fairly obvious fact. Clearly if the lines (the top and bottom fabric) stay the same length, the overall length of the quilt must get shorter.
But what if you keep going? There is a fallacy in this drawing: The thickness of the quilt is staying the same. Clearly the following is NOT what happens if you add even more lines:
These diagrams get more and more absurd, because of course what actually happens is that the batting gets hammered down, the piece gets thinner overall, and the fabric goes back to being flatter. And that means the overall piece should start getting LONGER again, at a certain point. That’s what I wanted to confirm and quantity, so I had Behemoth stitch twelve different test strips like these, each about a meter long:
Here is the diagram again, except this time the widths shown are real, measured widths from my experiment. (In the diagram below, the number of humps is real and the relative lengths are real, but the thicknesses are schematic, because I didn’t measure the actual thicknesses):
As you can see, there is a minimum length around 30 humps, and by the time you get to 200 humps (0.5cm line spacing) the thing is well on its way back to its original length.
Here is a plot of the lengths as a function of line spacing (the right-most data point represents infinite line spacing, in other words the original fabric length):
The interesting fact about this is that, because there’s a minimum, there are going to be two ways to get any given amount of shrinkage, a large-spacing way and a small-spacing way, one on either side of the valley. In order to get a quilt that lays flat, you don’t have to keep all the spacings the same, you can have zones of stitching width spacings on either side of the minimum.
These tests were all with lines in only one direction, but what if you add crossed lines in the other direction? I did a second set of twelve test strips with lines going in both directions, like these:
The following graph is a bit harder to read. The horizontal axis represents the line spacing in the direction of shrinkage (just like in the graph above). The vertical scale is again overall length of the piece. The lines connecting data points represent sets of similar spacing in the lines going the other direction. The bottom set has no cross-lines (i.e. it’s the same data points as the graph above, except a smaller number of them shown). As you go up, each line represents more and more closely spaced cross-lines. The data points are labeled with the line spacing in the shrinkage and crossed directions respectively.
The result is as expected: The more closely spaced the crossed lines are, the less shrinkage there is, regardless of how closely spaced the lines are in the shrinkage direction.
Now all we need to do is actually use this information to make something pretty that doesn’t warp…. In the mean time, we’ve been experimenting with the other solution: Stretching on a frame.
This quilt is “double-quilted”, using the term Nina invented for a thing I decided to try because why not. It’s basically a quilt on top of a quilt, so we can have a secondary level of relief that isn’t hammer down overall. I’ll write a full blog post about this technique later, but here’s a closeup that gives an idea of what it looks like:
Was all the quantitative measuring useful? Maybe…. So far I’ve used it only to create an interpolating function that I have used in some calculations involving how wide to make flaps that wrap around the wooden frame holding up stretched quilts like this. Hm, that’s probably another blog post too.
A wee taste of the progress Theo and I are making on our “Chad Gadya” embroidermation project.
Frames of the animation are stitched in groups of 6, arranged in a circle on matzo covers. We currently have 516 frames on 86 matzo covers, which I painstakingly finished by hand with multiple fabric layers and labels and everything.
We hired Theo’s daughter, Emma, to help. Here she is ironing away while I adjust a lining.
Here I am topstitching one of the 86 covers on a treadle sewing machine.
We have a lot of additional photography, stitchcoding and stitching to do, but we are making progress. When the film is done the matzo covers will be for sale.
I personally prefer Cycle B, because I like backgrounds where everything is moving – I feel it gives it more depth. As a 2-D design the clouds look nice, but in an animated cycle their stillness bothers me. I did make a version with moving clouds, but on this 24-frame cycle they had to be very dense to repeat:
Cycle C, “Repeating Clouds”. I still prefer Cycle B. The sky pattern might be a bit unconventional, but I think it’s stylish. Also I don’t like all that white in the background of A and C.
The palette is limited to 10 colors because this is destined for Embroidermation. The animated GIF doesn’t have great color fidelity; thread colors will look better and have more contrast between foreground and background.
If you have an opinion on which of these you prefer, please leave it in the comments and maybe it will help Theo and me settle our argument.
Back on the Quiltimation front, I was wondering if I could arrange animated frames on a quilt in a mandala/medallion pattern, rather than left-to-right cells. This would essentially be a quilted phenakistoscope, with the animation emerging as the whole thing is rotated (we’d keep the camera and lights stable, and rotate the quilt).
click for animated gif
The saturated colors here would be lost, although I could use a few colors of thread. The elements are early Leviathan designs, and Water from Chad Gadya which is still in (very slow) progress.
A great “machine’s-eye-view” of our quilt plotter is at the one-minute mark of this Apple promo video. In addition to creating the Mathematica user interface and co-founding Touch Press, Theo is Science Officer of our own PaleGray Labs.
The PaleGray Labs office/workshop/studio is in a former bank building, which is why our suite contains a vault.
Entering the Quilt Vault
When I bought a new mattress I stored the previous one in the office vault before it found a new home. I quickly realized the vault could be its new home, and the home of my art quilts, freshly returned from Sleepy Creek Vineyards. And so the Quilt Vault was born.
Even though Theo’s kids call the Quilt Vault a “sex dungeon,” having a real bed on site is practical for a quilt studio. I’m currently designing minimalist quilt tops using the 44″ wide bolts of colored fabric I bought last year, to have more colorful bases for complex stitch patterns. The bed provided instant visual feedback as I pieced this together:
PaleGray Labs being the textile art collaboration of me and Theodore Gray. First up, we have a photo of Mathematician Ian Stewart holding up PaleGray Labs’ “Fibonacci Sequins” quilt Theo just gave him in London:
This was designed by me and Theo using a Mathematica tool he created for that purpose, stitched on the new quilt plotter, and bound on my 100-year-old Davis Vertical Feed treadle machine. I hand-sewed on the sequins and beads. This was a test, but we plan to make more of them, including large bed quilts.
Below are some initial experiments with the quilt plotter. We’re still getting the hang of this thing, and working out some software issues that will require communicating through a Chinese interpreter some time in February after Chinese New Year vacations are over.
All stitchcoding by Theo using tools he built in Mathematica. Above we have fibonacci spiral fractals, a big guilloche pattern, and a modified dancing Reena Shah cycle from Sita Sings the Blues. All just tests, because the machine ripped the fabric before we learned to let it “cycle” on before moving the head (a problem that could be fixed with improved software, but until we get the ear of the Chinese software company that controls its operating system we just have to be very careful and do a lot of work-arounds).
Here’s my treadle-operated Davis Vertical Feed, which I am in love with. It makes binding almost a pleasure, a physical game of skill, a kind of meditation. If it weren’t for the time it takes to cut and iron the binding strips, I could see binding all PaleGray Labs quilts with this. (I’m also experimenting with bias tape and a Suisei binder attachment on my Singer treadle and Featherweight, which have the necessary mounting screw holes but lack the genuine walking foot that quality binding needs). Behind the Davis is the new 20″ long arm zig-zag machine, designed for making sails but which I intend to use for trapplique. It’s a powerful beast but we don’t get along because something’s wrong with its tension. The company is sending me a new tension assembly which will hopefully fix the problem.
The domain palegraylabs.com currently just reroutes to the “Quilting” category of this blog. Hopefully we (meaning I, helped by Webmaster Ian) will design a nice web site of its own soon.
…and smote the Angel of Death that slew the Slaughterer that killed the Ox that drank the Water that extinguished the Fire that burnt the Stick that beat the Dog that bit the Cat that ate the Goat that my father bought for two zuzim. Chad Gadya
…and slew the Slaughterer that killed the Ox that drank the Water that extinguished the Fire that burnt the Stick that beat the Dog that bit the Cat that ate the Goat that my father bought for two zuzim. Chad Gadya
…and killed the Ox that drank the Water that extinguished the Fire that burnt the Stick that beat the Dog that bit the Cat that ate the Goat that my father bought for two zuzim. Chad Gadya
Update: animation modified to show Shochet slicing from below. He’s still decapitating the poor beast, but it’s slightly more kosher for sticklers. Yes I know kosher slaughter involves slitting the animal’s throat, it just seems so grotesque that the cartoon shorthand of bloody decapitation expresses it best for me. But for those who consider slitting from below important, here ya go.