Thank you for the replies, and my sincerest apologies for forgetting to provide the image.
Here is the file:
https://drive.google.com/file/d/18g8...ew?usp=sharing
I tried your code a/b, and I also tried DanScott's suggestion about setting the source modulo to #0. Both improved the image, but it's still not quite there.
I'm very grateful to everyone for taking the time to help.