Skull Caps: Intarsia vs. Cross-stitch
The commonly accepted way to put a block of a single color onto a knitted item is a technique called intarsia. It's not complicated: you just keep a second ball of yarn, and when you get to a stitch you want to do in the second color, just use that second ball of yarn. This is how the diamond shapes in argyle socks are made, for instance.
Intarsia has limitations: it's only good for one color at a time, and it's made for back-and-forth knitting. If you knit a continuous tube, the yarn has to zigzag across the pattern every row. The red hat in the picture was made this way, and you can see that the skull area is bunched up because the zigzagging yarn behind it was a little too tight.
So when I made the black skull hat, I did the design in cross-stitch. Cross-stitching is usually done in colored thread on a woven fabric. What I do is the same idea but with yarn on a knitted fabric. To cross-stitch, you knit yourself a plain background and then thread your second color through a needle. Sew X's onto the knitted fabric.
Another advantage of cross-stitch over intarsia is that the X's of cross-stitch look a bit like square pixels, while the stitches in intarsia are V-shaped. (my next project is to figure out how to make some pixely computer graphic designs that I can't get sued for.)
Pattern
Yarn: Patons Classic Merino Wool, in black. My gauge: 4.5 sts/inch on #8 US (5 mm) needles. (Label gauge: 5 sts/inch on #7 US needles.) You'll use about half a skein of this, about 50g. You'll also need a small amount of white (I used the "Aran" color).
- On a circular needle, cast on 90 stitches for a women's medium-sized hat. Men with large heads should probably cast on 100.
- Join yarn and work in K1, P1 ribbing for about 1 inch.
- Switch to stockinette. Work until hat measures about 5.5" from bottom.
- Prepare for decreases: evenly space 7 stitch markers around your knitting (every 12-13 sts, if doing the women's hat). If you like, decrease a stitch where necessary to bring all the sections to the same size (12 sts). Switch to dpns.
- Decrease round: K2tog after every stitch marker. Knit one round plain.
- Repeat three more times for a total of four decrease rounds.
- Continue the decrease rounds, eliminating the plain rounds. (for a slightly pointier effect, as in the photo, continue inserting plain rounds between the decrease rounds.)
- When only one stitch remains in each section, cut yarn leaving a long tail. With a yarn needle, pull the tail through the remaining stitches like a drawstring.
- Finish by weaving in ends.
With the white yarn, cross-stitch this pattern onto the front of the hat. I think it looks best to line up the bottom of the crossbones with the bottom of the stockinette area of the hat (but feel free to place it wherever it looks best). You can make your stitches neat, small, and even, or you can be like me and make them big and sloppy.