Hello,
I noticed a problem in DOCX->EPUB (AZW3) conversion, but I'm not sure if it should be fixed. But I still think at least some warning would be nice.
The problem is that sometimes you may unknowingly use the font in WinWord which has only REGULAR version, but Word lets you use it with faux bold/faux italic. If you do this and convert to reader format with "Subset all embedded fonts", the same regular font file is embedded and subsetted multiple times, but then, Kindle (at least my Voyage) does use only ONE of the font files for all text using it. Then some glyps as missing depending on which of the subsetted font files the Kindle uses.
See attached files:
test - test.docx is testing docx file. 4 lines with Font1 are in Times New Roman, 4 following lines are with other font, visibly different to each other.
See winword.jpg for how it looks like on my system.
test-test.epub is conversion result with subsetting. It uses correct font and all glyphs for Font2, but not 'faux' versions. I leave it to Kovid if this is a bug or not, but I'd still think this deserves at least conversion warning. But is there anything like conversion warning right now? I know it may be hidden somewhere in conversion log, but some siren and red dialogue would be slightly more convenient
test1.jpg is how subsetted conversion to azw3 looks on my kindle. Uses regular font, but only some glyphs.
test2.jpg is non-subsetted conversion, I assumed it'd be enough for workaround but it doesn't look like it. I though calibre would use font from system, but it probably choses one of the subsetted font files saved in docx file.
So full workaround in this case is no subsetting in word, no subsetting in conversion and accepting huge files (for example Times New Roman is huge). And still, the conversion would not look the same as in winword, because faux-bold/italic is not converted.
BTW: How does the epub look on your reader? Because both Calibre viewer and Kindle Previewer do display it semi-correctly (no faux, but readable), which is slightly concerning...