Quick fix: Spread 4–5 stitches apart on the right needle tip before picking up the new color. This forces the float to span the full width of those stitches and prevents puckering at the color change.
What you are seeing
Your stranded colorwork fabric puckers or gathers at intervals where the non-working color is carried across the wrong side. The finished piece may be narrower than expected, won't lie flat, and loses the stretchy quality good colorwork should have.
Why it happens
- Floats (the yarn strands on the wrong side) are caught too tightly, pulling the stitches together
- Not spreading stitches on the right needle before carrying the float, so the float is measured against fewer stitches than it should span
- Catching floats too frequently in very long float runs, creating multiple tension points
- Knitting colorwork flat, which often leads to unconsciously tighter float tension
Fix it now
- For a finished puckered piece: soak in cool water for 15–20 minutes. Remove gently, press (don't wring) in a towel, then pin aggressively to the correct measurements on a foam blocking mat. Pull the fabric laterally while wet to open the floats. Leave to dry fully.
- For work in progress: spread stitches on the right needle before every float catch — fan them apart so the float spans the full group width.
- If floats span more than 5 stitches: catch every 4–5 stitches by looping the carried yarn around the working yarn on the wrong side. Do this loosely.
Prevent it next time
- The spreading habit: every time you pick up the new color, spread 4–5 stitches on the right needle first. Make this automatic.
- Hold both yarns in the same hand (Continental two-handed technique) to maintain consistent float tension.
- Swatch colorwork flat AND in the round — in-the-round colorwork is almost always more even.