[Scribus] RGB Images & Transparency in PDF 1.4

[Asif Lodhi]

Hi

(I posted this message a while back but didn't receive it myself from the 
Scribus maiing list. Posting it a second time just in case it didn't get 
through.)

The "Adobe Acrobat" section of the "DTP ToolBox" node (under the "Hints for 
Scribus Users") of the Scribus documentation (that comes bundled with the 
Scribus 1.2.2cvs) says:

"We are aware of one color mismatches with RGB images and transparency in 
PDf 1.4. Yes, this has been duly reported as a bug to Adobe too."

Would you elaborate more on it?

Does it imply that embedding non-transparent RGB images in PDF 1.4 will not 
cause problems?

Do _indexed_ PNG images also come in the "RGB image" category? Personally, I 
suppose not because in common graphics software "indexed" and "RGB" are 
treated as two different modes. Please clarify if I am wrong.

Does it imply that exporting a PDF 1.4 with embedded "indexed PNG" (with no 
transparency) images won't cause problems?

Somewhere in the same node/section, the documentation says:

"If you are creating Scribus files with transparency effects and export PDF 
1.4 (PDF 1.3 does not support transparency), you can enable Show 
Transparency Grid. "

Does it mean that exporting PDF 1.3 from Scribus with embedded images, 
transparent or otherwise, won't cause problems - considering the text quoted 
earlier? Does it also mean that exporting PDF 1.3 with embedded RGB images, 
with or without transparency effects, will get rid of the bugs, mentioned in 
the text quoted earlier, altogether?

Further, it would be of great help if the bug mentioned in the text quoted 
above could also be clearly explained further so that the documentation can 
be traced back to the original problem (and the related (original) causes as 
well) in addition to correlating the problem with similar problems being 
discussed on other mailing lists.

Please elaborate.

TIA
 
Asif
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