ImageMagick writes an image's colour space as its own object (`/ColorSpace 10 0 R`,
`10 0 obj /DeviceRGB`). Each source's copy of that object was never merged, since it
isn't a resource, so identical images compared unequal and every copy was kept:
8 copies of an 80 MB ImageMagick PDF combined into 648 MB instead of 81 MB.
Dedupe now compares a reference to a plain value (name, number, boolean or string) as
that value. The value objects themselves are still never merged. Combine, Insert Pages
and Reduce File Size share this code.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
