Thickness of lines not always regular

is this improved in dorico 4:
export slice in png (color) at 300 and 600: thickness of lines not always regular .
exemple at 300 (third line):
exemple at 600 second and third line thiner:
Best regards

Dorico gives you exactly what you ask for, so if you export at a particular dpi value that produces non-integral numbers of pixels for horizontal and vertical lines, then when exporting in monochrome this is the inevitable consequence, unfortunately. A bitmap graphic is a grid with a fixed resolution, and if the actual position of a line is halfway between two positions on that grid, when exporting in monochrome any pixel that is even partly overlapping with the true position of the line will end up black.

Ideally, exporting as PDF or SVG, which are vector formats, will give you much better results.

Bitmap monotone images are usually exported at 1200dpi to avoid visible pixellation effects.

thank you for the explanations, now I undestand, indeed I exported for a web page with a background other than white so that I exported in monochrome
yes in general I export in svg but I tested in png with 1200dpi and it’s ok Thanks

When exporting PNG (color) you do get transparency.
You don’t have to go for monochrome images.