[Scribus] transparency question

[jon]

> Hi,
>
> This regards using png images with portions that are
> 100% transparent.  What seems to happen is that this
> kind of transparency is respected even when exporting
> to PDF 1.3 (as seen in acroread and kpdf), which is not
> what I was expecting.

You are right PDF1.3 does not support transparency
and as far as I know scribus is not able to reduce/rasterize  
transparency to pdf.

> So I'm wondering if this is
> too good to be true, that I may be able to use this
> kind of transparency without restriction on what PDF
> version to use, maybe even PDF/X-3...

Sorry, no. X3 is 1.3 based and therefore does not support transparency.

> The question is,
> can I rely on this behaviour?

If it is so - ? - it would be kind of a violation of pdf standard  
definitions.
If a pdf is tagged to be ² 1.3 or ² X3 AND includes transparencies  
RIPs will reject
the pdf or will give you false results.

> What I guess was expecting was that since "PDF 1.3 does
> not allow transparency" the transparent part of the png
> would be made white, or maybe black.

"Normally" the whole or partial element(s) will be block out at least  
when printing seperated.

Any reason not to use 1.4?
Jon