The built-in driver for the Zebra LP2844 on macOS ("Zebra EPL2 Label Printer", see https://youtu.be/DT6gnpzzU60) gives pretty crappy print quality.
The latest (unreleased, as of Aug 2023) version of LPrint does better, see michaelrsweet/lprint#91 (comment).
I think the new "special algorithm" doesn't actually do much. It may just be that print-color-mode=bi-level
, aka Print Mode: Text (which thresholds the image instead of trying to use dithering to cover the whole grayscale range) wasn't actually working in 1.2.0, and all the changes with the new algorithm accidentally fixed that bug. I see no visible difference between bi-level
and monochrome
; monochrome
should, in theory, be thresholding only the parts that "look like a barcode", leaving the other parts dithered like before, whereas bi-level
should be thresholding the whole thing.