What is wrong with my decreases?

I’m working on a shawl project. It is made of two halves which are mirror images of each other. I used the k2tog decrease, and one turned out nicely, but the other has a ridge in between the stockinette stitch and the seed stitch border. Why? Any suggestions or advice?

See the pictures below for a comparison.

K2tog is a right leaning decrease. It will look different on one end especially if it’s angled differently. What you probably needed to do was use a left leaning decrease on one side. There is no perfectly identical matching decrease, but most commonly used is the SSK. There are videos of decreases in the video section.

Yep, a k2tog leans / this way which makes it lean toward the edge at the beg of the row and towatd the center at the end. So you probably should have used a skp/ssk at the beg which leans \ toward the center too.

What Sue said makes good sense to me, but I tried a small swatch two different ways and it seems that the SSK in this case looks best at the end of the row right before the seed stitch border and the K2 looks good at the beginning right after the seed stitch border there. I have a hard time crediting my eyes on this one. I suggest trying a small sized swatch of the two different possibilities (the way I said, or SSK at the beginning and K2tog at the end), and see what happens.

Thank you both for the tips. I have not done too many rows of my knitting, so I will unravel it and try the ssk decrease. The information will come in handy for future projects; now I know when to use right-slanting or left-slanting decreases.

The ssk at the beginning will look like her k2tog at the end of the row, giving the dec a ‘chain’ effect. It’s because of the outermost st of the 2 ending up on top.