Can't say ZIP compression is "objectionable" and if we wanted compression, that's what we'd choose.ZIP compression is loss-less, why is it objectionable for you?
Of course you know that if your PDF file is any version beyond PDF 1.5, there in fact lossless ZIP compression applied to your object streams within your PDF file. Those object streams include but are not limited to all your text and vector content.
Unless your systems and/or RIPs are running on ancient platforms from well over a decade ago, the overhead of decompressing ZIP compression is truly minimal. (BTW, all current Microsoft Office .docx, .xlsx, and .pptx files are in fact ZIP files!)
Hmmm. Something tickling me about 'Flate encoding' . . . . yes - this concerns multiple issues regarding multiple streams of data.Next tried: Clean up>leave compression unchanged AND unchecked "Use Flate to encode streams that are not encoded".
Thanks for the ideas!
Screen shot was only intended to show settings that do NOT give me ZIP compression out of InDesign.
In any instance when we save PDF made with these settings, we end up with ZIP'ed images.
I've tried Optimized save: Images>Compression>Retain existing
Also tried: Clean up>leave compression unchanged
Both still delivered ZiP"ed images.
Next tried: Clean up>leave compression unchanged AND unchecked "Use Flate to encode streams that are not encoded".
This saved file without ZIP'ed images.
probably spent more time testing than we'll save at the RIPs in the next 6 months :>}
chriscozi:Hmmm. Something tickling me about 'Flate encoding' . . . . yes - this concerns multiple issues regarding multiple streams of data.
You really DO want 'Flate' because you may/will face serious file corruption issues down the road.
If memory serves:Never having disabled Flate before I can't say that I've had any issues associated with or without it. What kind of issues did you experience?
… And btw Adobe's PDF settings default to using JPEG compression. Even in PDF X-4 PDF settings which is baffling. Do yourself a favor and never use JPEG compression. Always use ZIP compression.
That really is not quite true! The default image compression for PDF/X-4 (and for that matter most of the joboptions for PDF export are as follows:
View attachment 290819
Automatic (JPEG) is not the same as JPEG. You ask “what's the difference?” Good question!
JPEG results in all images being JPEG-compressed with the image quality specified.
On the other hand, if Automatic (JPEG) is specified, the image is examined and if the image is really simple vector or text content in raster format, lossless ZIP compression is used in lieu of JPEG compression resulting in higher quality and no JPEG compression imaging artifacts! And if the resultant image has no more than 256 distinct colorants, indexed color is used to save space.
Note that there is a similar set of settings for you JPEG 2000 fans, Automatic (JPEG 2000) versus JPEG 2000 compression with similar characteristics.
Note - to put to rest a long-lingering misconception by industry Luddites, there is absolutely no loss of image quality using ZIP (otherwise referred to as flate compression) in a PDF file or for that matter in TIFF files. (Likewise, LZW compression, not typically available with current PDF tools but commonly used in TIFF files, maintains full image fidelity although typically with not as much compression advantage that ZIP-compression provides!)
- Dov (no longer @ Adobe!)
But if it is a photographic image it will use JPEG compression, correct. Not cool Adobe...not cool at all. And don't get me started on "text content in raster format". Ugh.
For the vast majority of photographic images that are properly focused (and sharp) and not ridiculously cropped / magnified and then artificially up-rezzed, maximum quality JPEG compression in the PDF file used for printing typically yields perfectly acceptable results for the vast majority of printing and display situations. Note that I would absolutely never advocate storage of digital master images that are subject to editing (and possibly multiple stages and rounds of editing) to be stored in JPEG or even JPEG 2000 (other than lossless JPEG 2000) formats. For that purpose, personally, I typically use ZIP-compressed TIFF with ICC color-managed 16 bits colorant per pixel storage coming out of Camera Raw! (Typical RAW images from professional digital cameras are natively and typically 10 to 12 bits colorant per pixel. Conversion to 8 bits colorant per pixel is in fact lossy.)
Adobe does not require any use of JPEG compression. You are quite free (and encouraged) to make your own joboptions that meet your particular needs or religious beliefs. That having been said, general industry experience is that the default Automatic (JPEG) setting in fact does meet the photographic image quality requirements of the vast majority of graphic arts customers. Is there some lossiness with even maximum quality JPEG compression of photographic images? Of course there is! But most customers are not viewing such images and comparing them with originals with very high-powered loupes! And that is exactly why the default settings with regards to compression are as they are!
I certainly don't disagree with regards to text or vector content in raster format. The sad news is that all too often such content (including, ugggh, logos) is provided to graphic artists who have no choice in the matter. The only common situation in which graphic arts applications themselves force text and vector graphics into raster formats is when users improperly flatten transparency when creating a PDF file. That is exactly why knowledgeable industry experts advise use of PDF/X-4 with full ICC color management and without any transparency flattening. Issues of transparency are best handled by the RIP during final rendering!
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