japbcoelhoandClaude Opus 5.5 0ce21b476c PDF: transparency groups blend in CMYK in print exports ...

krilla gives every transparency group it writes a DeviceRGB blending space,
including the group around a placed PDF page:

  /Group<</Type/Group/S/Transparency/I true/CS/DeviceRGB>>

A print file therefore carried DeviceRGB (forbidden by PDF/X-4 under a CMYK
output intent) and blended CMYK art through RGB: a placed logo's black,
C91 M78 Y61 K97 in its own file, printed as C72 M67 Y67 K88. When the
document's transparency blend space is CMYK (the default for print) or the
export is PDF/X-4, the groups are rewritten to /CS/DeviceCMYK in place and
at the same length (the optional /Type/Group gives the room, the rest is
padded with spaces), only inside object dictionaries found through the
cross-reference table, so every offset stays valid. Booklets get the same.
Books merged by merge_pdfs are not covered.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2026-10-06 09:05:03 -04:00

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src

PDF: transparency groups blend in CMYK in print exports

2026-10-06 09:05:03 -04:00

Cargo.toml

P: place EPS through its preview or a bounding-box placeholder

2026-10-03 07:19:54 -04:00