[tlbuild] writepng.c: No transparency with PDF/A-1b

[Florian Breitwieser]

Hi Martin, thanks for the reply and the cross-posting.

> AFAIK it's based on 1.3 (the main addition of 1.4 is transparency),
> so can't you just set pdfminorversion to 3?

No, PDF/A-1 is based on v1.4, but PDF/A only supports a subset of the
features [1]. One of the additions in 1.4 is metadata streams using
XMP, which is also a requirement in the PDF/A formats.

Best,
Florian

[1]  http://en.wikipedia.org/wiki/PDF/A and http://en.wikipedia.org/wiki/Pdf