Some legacy Windows software, certain embedded systems, the odd POS printer — all still want BMP. You wouldn't pick BMP for anything new, but sometimes you need it.
What BMP is
BMP (Bitmap) is Microsoft's original image format from the late 80s. Uncompressed, simple, supported by every Windows app ever shipped. Huge files because it has no compression, but bulletproof compatibility with old software.
When you'd need it
Three reasons usually: legacy software that only accepts BMP, embedded systems with very limited image-format support (label printers, industrial displays), or a specific compatibility requirement set by a stakeholder.
For any modern workflow, PNG or JPG will be better in every dimension except compatibility with software from 1998.
Convert via the format hub
Flint's convert hub supports BMP as an output format. Drop your PDF in, pick BMP, get one BMP per page. File sizes will be much larger than equivalent PNGs — that's BMP for you.
Practical tips
Keep DPI moderate. A 300dpi BMP of a single page is around 20MB. If your destination doesn't need archival resolution, drop to 150dpi and save the disk space. For label printers and similar low-resolution targets, often 96dpi is sufficient.
FAQ
Why so big?
BMP has no compression. Every pixel takes its full storage. PNG and JPG both compress meaningfully.
Can I get colour and greyscale?
Yes — pick the colour depth in the converter. Greyscale halves the file size vs colour.
Multi-page BMP?
BMP doesn't support multi-page within a single file. You get one BMP per PDF page.
Is BMP becoming obsolete?
In modern workflows, yes. For legacy compatibility, it's still occasionally required.
Legacy needs, modern conversion. Convert your PDF to BMP for the systems that still need it.