DPI is a sampling choice, not a repair operation
The useful relationship is pixels = PDF points × DPI / 72. A 612-point-wide page becomes 1224 pixels at 144 DPI. Doubling DPI doubles both dimensions, so the pixel count grows roughly fourfold. File size does not have to grow by exactly four: image content and compression matter.
A higher setting gives vector text more samples, but cannot reconstruct detail missing from an embedded scan. If the original page contains a blurry photograph of a table, a larger raster may simply contain more pixels describing the same blur. Inspect the result at the actual intended display or print size.
PNG and JPEG answer different needs
PNG is lossless for the rendered bitmap and is a good first choice for text and line work. That does not mean lossless conversion of every PDF feature: vectors and searchable text have already become pixels. JPEG may be useful for photographic pages or smaller delivery files, but compression can affect fine lettering. This tool uses a white background for image output.
Page numbers and retained meaning
Filenames use original 1-based PDF page positions. They do not know the report's printed page labels. Keep the source filename and page range in your delivery note if another reader must locate the original. Page-image export is not a source-verification or evidence-authentication system.
Annotations and form appearances depend on rendering behavior; interactive controls do not survive as controls. A PNG/JPEG does not retain a PDF digital signature, selectable text or editing structure. The first version does not accept password-protected documents.
Rasterization is not secure redaction. Sensitive content can remain visible, and the tool does not inspect or certify privacy. It also does not modify the original PDF.
Complete any needed text edits or annotations before creating the raster copy. The related KomoPDF offers a broader editing and annotation workflow, while this CLI only exports pixels. Neither that distinction nor exporting an image should be treated as a secure-redaction guarantee.
← Field notes