Problem with both top and bobbin thread?
I was sewing string blocks and didn't notice any problems because of the thread color. However, on the last one, I switched the thread in both to another color and then noticed the bobbin tension was too tight. Loosened it a quarter turn (Janome 770), changed the bobbin thread to another color (same brand, same weight) and then the stitches were the same. I did the stretch test and it broke in the same place, and I did a zig zag on doubled fabric and it was ok, but still showed here and there on the bottom, and in a couple of places, the bobbin thread showed on top. Then I doubled some fabric and did some straight stitches and the top thread shows clearly on the bottom and the bobbin thread shows clearly on top. Not a lot, just a dot where the needle goes through.
Is this normal?
Everything I've read said the two stitches should meet in the fabric and not be visible. When I tripled the fabric, the top stitch looked fine, but on the bottom, I could see the loop of the top thread and the bobbin thread looked flat on the fabric, like it wasn't pulled into it at all.