Alternate in ICC stream dictionary and PDF/A-1b

[a20god]

Dev Effort

1D

Description

verarPDF 1.7.2 claims that this document conforms to ISO-19005-1:2005:
ICC-Alternate-1.pdf
However, the Alternate entry of the output intent's DestOutputProfile (which is not to be ignored in PDF/A-1, in contrast to PDF/A-2)

• is a device color space which violates 6.2.3.3 (DeviceCMYK vs. RGB output intent)
• does not have the same number of components as the ICC profile (4 vs. 3), see PDF Reference 1.4 Table 4.16.

[bdoubrov]

Well, strictly speaking this is a violation of the PDF specification. This is a bit similar to the invalid N entry. This has also been discussed already at the Validation Technical Working Group. But I'll double check this again.

[a20god]

The document clearly violates 6.2.3.3 (DeviceCMYK vs. RGB output intent).

[THausherr]

Related? Attached PDF validates with VeraPDF (1.14.7-RC) despite a flaw: the /Alternate of the ICC colorspace (at Root/Pages/Kids/[0]/Resources/XObject/Im1/ColorSpace/[1]/Alternate) is /DeviceRGB while the colorspace is a grey one and N=1.
PDFA-Bad-ICC-Alternate.pdf

[bdoubrov]

Yes, indeed the document does not comply to PDF 1.7 specification, and veraPDF does not perform the full PDF validation, just PDF/A.

We catch some of the critical syntax errors and report them to the stderr, but not that one. We'll add this check, as having an alternate with a different number of color components is a quite severe error.