I’ve been working on a koi fish quilt for a while. I wanted those heavily scaled koi with repetitive black background under orange-red scales. If it sounds easy, I’m saying it wrong.
This is a zoning issue. You have a black zone and a colored scale zone. They need to be crisply separated.
The gold standard approach is to make each scale separately, tie them off, and start the next one. By one. By one.
It does make a nice separation. It also asks the question, “How long do you expect to live?” It takes forever.
The other answer is to do one zone at a time and find a pathway through your stitching that makes the least mess getting from one spot to another. You need to find a stitching pattern.
It’s different every time. You want to cover the areas where you’re moving from one square to another with the smallest, least visible stitch.
What works best is the stitch moving your zigzag directly out from the side. You’ll get a straight line that later can be covered over. Or if it’s tiny enough, ignored.
I chose to take black thread afterward and clean up the image. This is half fixed, half not. I’m sure you can see the difference.
It’s always simpler to blend colors. But sometimes what you want is that crisp distinction between zones.