I was amazed to see that most people couldn't figure out how to do it, so I thought I'd publish instructions that I've never written down before, but that let me make a batch of Harry Potter scarves. This is set up to make the kind of scarf that is closest to the ones in the movie in the easiest possible way.
Harry Potter Scarf
Yarn needed: Choose a yarn that's about a DK or light worsted weight in the school colors of your choice. I'll discuss colors at the end of the instructions. For a wide-stripe scarf (like in the first two movies) about 220 yards of each color. For wide and narrow-striped scarves (like in the third and remaining movies) you'll need about 420 yards of the main color, and 120 yards of the contrasting color. This can be acrylic, wool, or a combination of the two. You might want to give some consideration to the washability of the scarf if it's for a child.
Tools and notions needed:
- One 16 inch circular needle in the size you use for DK or light worsted. I'd choose a size 7 or 8, but you need to choose a size that gives you a nice, supple fabric. Not too tight or too loose.
- At least one stitch marker (occasionally, these pop off. You only need one, but I would want to have some extras in case of loss).
- A hardback book (any of the Harry Potter hardback editions are perfect).
- A garment steamer or steam iron (if you don't have either of these, you could wet block it if you know how to do that, or look it up on the internet).
- An insulated cooking mit (silicone works best). This is optional, but may be helpful if you're steam blocking.
- Crochet hook that's an appropriate size for the yarn. The size is not important because you won't be crocheting with it, but you'll be pulling the fringe through, so it has to be big enough. You can use a latch hook instead of a crochet hook, and that might even be easier.
Using main color, cast on 80 stitches. Place a marker, and knit in rounds for the length of the scarf following directions for type of scarf.
Wide Stripe scarf: Knit with MC for 4 inches, then switch to CC for 4 inches, and repeat for length of scarf, ending with a MC stripe. Change colors at the marker, knotting yarn together with a square knot, and leave ends inside the tube, trimming ends to about 4 inches. You don't have to darn these ends in. When the scarf is about 72 inches, ending with a MC stripe, bind off. You can make the scarf shorter for a small child. It can be tried on to see if it's so long the child will trip on it.
Wide and Narrow Stripe scarf: Knit with MC for 6 inches, then switch to CC for 4 rows, switch to MC for 6 rows, and back to CC for 4 rows. Repeat this sequence for length of scarf, ending with a wide MC stripe. Change colors at the marker, knotting yarn together with a square knot, and leave ends inside the tube, trimming ends to about 4 inches. You don't have to darn these ends in. When the scarf is about 72 inches, ending with a wide MC stripe, bind off. You can make the scarf shorter for a small child. It can be tried on to see if it's so long the child will trip on it.
Finishing: Lay the scarf out on an ironing board or other steam-resistant surface, making sure that the jogs for the color changes are on one side edge. If the yarn you used is overtwisted, the jogs may not line up, but twist and flatten the scarf with your hands so that they do line up along the edge. Steam the scarf with a steamer or steam from a steam iron. Do not press down with the iron. You can pat it into shape using a mitt type pot holder over your hand (silicone ones work great at keeping your hand safe from the steam). Let the scarf sit until it's dry and cool. The scarf should now look professional, and the ends should lie flat. If they don't, though, don't worry. We're going to fix that with the fringe.
Choose the MC, and wrap it around a hardback book 7 or 9 times. Do count the number of wraps and make them consistent throughout. The number of wraps is less important than consistency. If it looks like you're short on remaining yarn, you could go down to 5 wraps for each fringe. Once the proper number of wraps has been made, cut the loops on the side of the book that opens. There will be a natural indentation where the pages are so you can get your scissors in there.
Insert your hook (crochet hook or latch hook) through both thicknesses of the scarf on the end, about a quarter inch in from the side, catch the middle of the loop of yarns (fringe) you just made, pull through the scarf, and pull the ends of the fringe through the loop. Pull the ends of the fringe gently to tighten up the lark's head knot you just made. Make another clump of fringe on the other side of that end, about a quarter of an inch from the edge. Then make another MC fringe in the center of the end. You can fold the end in half to see where the center is. Make another MC fringe equally spaced between the center fringe and one edge fringe (fold again to see where that is), then do the same thing between the center fringe, and the one on the other side. Switch to CC, and make a fringe between each of the other fringes. This will space them out equally and give you the same number of fringes that alternate in color.
Fringe the other end the same way. Place the scarf on a table, with the fringe at the edge of the table so that just the uneven ends of the fringe stick out over the edge. Trim off the ends of fringe that are too long by cutting along the edge of the table.
Wear and enjoy!
Griffindor: MC is burgundy, CC is gold.
Ravenclaw: Book colors are: MC is a medium blue, CC is bronze, which is between gold and copper. Movie colors are: MC is navy, CC is silver grey.
Hufflepuff: MC is yellow, CC is black.
Sitherin: MC is Green and CC is silver.
That's it! Good luck on making your very own Harry Potter scarf!