[Scribus] pictures too dark

[PLinnell]

On Friday 22 July 2005 22:06, robert wrote:
> On Friday 22 July 2005 13:48, Craig Bradney wrote:
> > On Friday 22 July 2005 08:41, robert wrote:
> > > On Thursday 21 July 2005 18:17, PLinnell wrote:
> > > > On Friday 22 July 2005 01:11, robert wrote:
> > > > > I've just starting using 1.3.0 (July 14, 2005 build) and I
> > > > > can export just fine. The problem is the pictures look very
> > > > > dark in Reader (7.0). I've got the export set for
> > > > > screen/web and I didn't find anything in archives. Just out
> > > > > of curiousity, I also loaded the pdf up in xpdf, and while
> > > > > the fonts look bad, the pictures are fine. Can anyone
> > > > > explain what's going on?
> > >
> > > A follow-up:
> > >
> > > I found an old copy of Scribus (1.2.1, Jan 08, 2005) on my HD,
> > > so I decided to see if that has the same problem. I created two
> > > new pdfs, containing the exact same picture, one from Scribus
> > > 1.2.1 and the other in Scribus 1.3.0. Surprise! The 1.2.1
> > > version displays just fine, while the 1.3.0 pdf is too dark. I
> > > checked the export options and can't find any differences.
> > >
> > > Then I got another idea, "What if I load the image up in the
> > > GIMP and convert it to jpg?". It was originally a png (with an
> > > alpha channel). Well, I did that and now the jpg based 1.3.0
> > > pdf displays fine. So it looks like a Scribus problem after
> > > all, but it only affects Reader in Linux. Arggggh! Well, at
> > > least I have a work around.
> > >
> > > Can anyone with a more current Scribus (after July 14, 2005
> > > build) confirm this for me? Do pngs display too dark? I'll file
> > > a bug report, but I'd like to know it's not just me first.
> >
> > You will still get issues with dark images with JPG format on
> > Acro Reader on Linux. It will depend on the PDF version etc you
> > are exporting as transparency is one of the things that triggers
> > it. There is an Acro Reader bug as Peter has said.
> >
> > Craig
>
> OK, except for two things: 1) JPG doesn't support transparency, and
> 2) I did not get the same behavior using Scribus 1.2.1 (using the
> original png image).
>
> Does 1.2.1 do something, or not do something, that 1.3.0 does?

You must explicitely enable transparency in 1.2.x to enable PDF 1.4 
features. 1.3.x will automatically enable transparency *if* you 
export PDF 1.4.

It is *exactly* the combination of transparency plus exporting 
"Screen/Web " or RGB PDF which seems to trigger the poor colors in 
Reader 7. We now have a fair amont of example files which exhibit 
this behaviour in Reader 7. An RGBA png will trigger this pretty 
reliably and in some cases cause some extreme shifts of color. This 
has been re-produced by others with PDF files not created in Scribus 
at all.

I took the file you provided and exported PDF from both 1.2.2.1 with 
transparency enabled and 1.3.1cvs  for PDF 1.4. 

The results look very much the same in Reader 7, Reader 5 and most 
tellingly in Photoshop 6 when I compare them side by side. If 
anything the 1.2.2.1 PDF looks *very* slightly darker in Photoshop 6. 
When I use the color picker, the colors on the edge pixels match very 
very closely.

So, in this case, I remain convinced its a bug in Acro 7 on Linux. Is 
Scribus doing something wrong ? No, it just creates PDF in a way 
which can trigger it easily.

Cheers,

Peter