General expectations for PDF file size

[ReflexBlueHorror]

I can't find much discussion in other forums about the expected file sizes of generic book jobs.

For example, a 32pp 4/4 magazine or children's picture book with 300dpi images, or a 6 " x 9 " 224pp 1/1 novel.

Asking as I'm following the Ghent Workshop PDF/X workflow for a current job but my 32pp 2/2 (vector + 600dpi greyscale [.tif with LZW compression] + 2400dpi bitmaps [.tif with LZW compression]) is coming out at 2 GB.

I don't know whether that sort of file size is expected or an indicator something is wrong (I'm used to PDF export for online publication, not book publishing). There are no preflight warnings though.

 

[DCurry]

That is a huge PDF. 600ppi is overkill - you can set that to 300. When you say 2400ppi for bitmaps, do you mean 1-bit images (if you open it in Photoshop it would say Bitmap mode)? If it's just a photograph you can set that to 300 as well.

Can you post a screenshot of your PDF settings? You don't mention what kind of compression you are applying at the PDF export stage. Usually it would be ZIP or JPEG, not tif/LZW. JPEG Maximum Quality is good for most cases. If your images have a lot of fine detail or rasterized type, you might want ZIP compression instead.

If you already know who your vendor is, they can probably provide you with a PDF preset that is customized for their needs.

 

[jwheeler]

When I was in pre-press, we would get massive files like this that really didn't need to be. Often, the designer was afraid of allowing any image compression in fear that it would not print as sharp. Now-a-days, if you just use the default "Press Quality" settings, making sure to turn on bleeds and crop marks, you will be fine. Additionally, as DCurry mentioned, sometimes your printer will have a preferred preset they can provide you.

 

[DCurry]

I would add that if you start with the default press quality settings, please change the marks offset to be at least as large or larger than the bleed. Otherwise your marks will interfere with the bleed and render it useless.

 

[abc]

Are you using the Ghent Workgroup output settings to make the PDF, or just preflighting using the Ghent Workgroup settings.
Here are the output settings for various applications. https://www.gwg.org/application-settings/
The Preflight Profiles don't nornally need downloading as most applications have them built in.

As stated previously those are really big files, not something I would expect from Ghent settings. (PS I'm a member of the Ghent Workgroup)

 

[wonderings]

When I was in pre-press, we would get massive files like this that really didn't need to be. Often, the designer was afraid of allowing any image compression in fear that it would not print as sharp. Now-a-days, if you just use the default "Press Quality" settings, making sure to turn on bleeds and crop marks, you will be fine. Additionally, as DCurry mentioned, sometimes your printer will have a preferred preset they can provide you.

That is what we do. Will get a link to a massive PDF from the client, I will drop it in indesign take a look make sure everything is ok, re-save as a high quality PDF and 9/10 times it is small enough for me to send back through email.

 

[Schnitzel]

That is what we do. Will get a link to a massive PDF from the client, I will drop it in indesign take a look make sure everything is ok, re-save as a high quality PDF and 9/10 times it is small enough for me to send back through email.

Take cover, I think Dov Isaacs isn't going to be happy with your workflow...

 

[ReflexBlueHorror]

Found the cause of the 2 GB file - my own export checklist had compression to be manually set to none. That said, the GWG seems still seems pretty large for a 32pp book. The initial (tampered with) GWG settings:

The newly exported PDF with GWG2015_CMYK_CS5-CC_350ppi:

The newly exported one came out at 144 MB which to me still seems enormous for a 32pp illustrated book but I don't know what would be usually expected for that sort of print project.

In Photoshop I'm using 600ppi based on commentary that 300ppi is too low to take advantage of FM screening for single-color greyscale art.

Both the 600ppi greyscale 8-bit images and 2400dpi bitmaps 1-bit are saved with .tiff extension and LZW compression:

The files used in the InDesign document consist:

45 files x 600ppi greyscale 8-bit .tiff LZW compression
average file size 6 MB
total size 262 MB

41 files x 2400ppi bitmap .tiff LZW compression
average file size 500 KB
total size 22.4 MB

40 files x 2400ppi cmyk .ai
average file size 1 MB
total size 39.3 MB

 

[abc]

That's a bit more reasonable considering the image resolutions you are working with.
i can't comment on the resolution needed for FM, that might provoke discussion, but what you have now should produce a nice job.

I wouldn't worry about the size. Trust me, your printer has seen a lot worse!!

 

[Repro_Pro]

Whenever we produce a PDF that seem abnormally large, we re-save that PDF using Acrobat (no change to any parameter).
In many cases the new PDF file size diminishes significantly.
I have no idea why this happens.

 

[DCurry]

600 still seems high even for FM screening, but it certainly won't hurt anything (other than increasing your file size as you already know.)

Since you've gone through the trouble of using 600ppi, you also need to make sure that your print vendor doesn't inadvertently downsample to 300 in their workflow. I know that our standard RIP settings are set to automatically take everything down to 300 unless we manually intervene and a lot of people either forget about it or don't realize it's happening in the first place. Or, they do it the first time, then there are corrections or new files submitted and they forget to honor the 600. I know because I've done it!

 

[jwheeler]

The newly exported one came out at 144 MB which to me still seems enormous for a 32pp illustrated book but I don't know what would be usually expected for that sort of print project.

That seems much more reasonable for a 32pp document. I wouldn't think twice about a file being that size if I received it. I'd actually be glad to see that it wasn't too small, which would concern me that the quality would be bad. Illustrator can produce really large output files because of all of the points, gradients, and transparency effects that people use these days. Nothing wrong with it...just the way it is.

 

[Joe]

Disk space is cheap these days as is high speed internet. We do not use JPEG compression even at the max quality setting as we have seen image degradation at that setting. We use ZIP compression only! A bit larger PDF file size but zip compression is lossless while JPEG compression is lossy even at the max quality setting.

 

[Dov Isaacs]

That is what we do. Will get a link to a massive PDF from the client, I will drop it in indesign take a look make sure everything is ok, re-save as a high quality PDF and 9/10 times it is small enough for me to send back through email.

Really not a good idea! Better you should examine the PDF file in Acrobat Pro and if appropriate downsample the images if those really have excessive resolution. However, it makes very little sense and can actually be harmful to quality to do multiple rounds of image downsampling. Each time you downsample, a certain amount of lossiness is introduced into an image. For example, if optimally you want 300dpi resolution for your images and your existing images are 1200dpi, go for such downsampling (use Acrobat's Preflight fixup's or the Optimized PDF save for this). But for images in less the 450 to 500dpi, don't waste your time.

BTW, despite the belief of most in prepress that 300dpi is a magic number and that if you use this for device resolution, you avoid resampling at the RIP. This is totally untrue. All images are resampled during RIP / rendering process, just another place where some detail may be lost. Bottom line, avoid cascading rounds of image downsampling!

- Dov

 

[Dov Isaacs]

Disk space is cheap these days as is high speed internet. We do not use JPEG compression even at the max quality setting as we have seen image degradation at that setting. We use ZIP compression only! A bit larger PDF file size but zip compression is lossless while JPEG compression is lossy even at the max quality setting.

Whereas I would agree with you wrt/ how inexpensive disk space is and per my posting wrt/ resampling I would avoid cascading rounds of decompression, downsampling, recompression - especially with JPEG, JPEG compression at maximum quality is generally not a problem for photographic types of images and reasonably high resolution. Raster images of what would probably have been better represented as either text or vector images should never be JPEG-compressed. ZIP compression is much more appropriate and lossless.

In Adobe applications such as InDesign and Illustrator, you should use the “Automatic (JPEG)” at “Maximum Quality” for images. Why? The “automatic” aspect of this is that we examine each image as we produce and export the PDF file. If the image is “vector-like” we compress with lossless ZIP compression, avoiding those nasty JPEG imaging artifacts and lossiness. If the image is photographic (i.e., something that would typically come out of camera), we apply JPEG compression at the special quality setting. For the vast majority of printing applications, this works out without any perceptible quality loss. (BTW, unless your image workflow uses RAW images followed by use of TIFF or PSD subsequently as opposed to out-of-camera JPEG, you have already suffered through a round of image lossiness!)

- Dov

 

[Schnitzel]

The “automatic” aspect of this is that we examine each image as we produce and export the PDF file. If the image is “vector-like” we compress with lossless ZIP compression, avoiding those nasty JPEG imaging artifacts and lossiness. If the image is photographic (i.e., something that would typically come out of camera), we apply JPEG compression at the special quality setting.

- Dov

That's interesting. How does the software know what type the image is? Image analysis? Number of unique colors in the image, sharpness of edges or something similar?

 

[Dov Isaacs]

That's interesting. How does the software know what type the image is? Image analysis? Number of unique colors in the image, sharpness of edges or something similar?

It carefully analyzes the image and works exceptionally well. The code exists not only in PDF export/save from InDesign and Illustrator, but also in the Distiller in converting PostScript to PDF!

- Dov

 

[Joe]

Whereas I would agree with you wrt/ how inexpensive disk space is and per my posting wrt/ resampling I would avoid cascading rounds of decompression, downsampling, recompression - especially with JPEG, JPEG compression at maximum quality is generally not a problem for photographic types of images and reasonably high resolution. Raster images of what would probably have been better represented as either text or vector images should never be JPEG-compressed. ZIP compression is much more appropriate and lossless.

In Adobe applications such as InDesign and Illustrator, you should use the “Automatic (JPEG)” at “Maximum Quality” for images. Why? The “automatic” aspect of this is that we examine each image as we produce and export the PDF file. If the image is “vector-like” we compress with lossless ZIP compression, avoiding those nasty JPEG imaging artifacts and lossiness. If the image is photographic (i.e., something that would typically come out of camera), we apply JPEG compression at the special quality setting. For the vast majority of printing applications, this works out without any perceptible quality loss. (BTW, unless your image workflow uses RAW images followed by use of TIFF or PSD subsequently as opposed to out-of-camera JPEG, you have already suffered through a round of image lossiness!)

- Dov

Agreed. For the vast majority...which is why I prefer to use ZIP because it always works without any quality loss.

 

[Ulrich]

Whenever we produce a PDF that seem abnormally large, we re-save that PDF using Acrobat (no change to any parameter).
In many cases the new PDF file size diminishes significantly.
I have no idea why this happens.

One reason is, ​

because: If you re-save (with "save as") you kill the history of changings in a document. Only the latest, actual state of the document will be written.

An other reason for unnecessary growing of a PDF-file coud be: Depending from the Export Settings sometimes much to much icc-profiles (each about 1-2 MB) were added to objects. For an example PDF/x-3 add (often) the same CMYK-profile to former not calibrated pictures and text aditional to the Output intent… ;-)

Ulrich

 

[Repro_Pro]

Thanks Ulrich,
But, if Illustrator saves history inside the pdf and that info is not available to us, then such behavior is clearly counter-productive.
Beyond that, why would Acrobat strip any info "silently" when a file is simply saved AS IS?
BTW, I believe Acrobat doesn't strip the native Illustrators' file structure, that we actually want to keep.
I wonder if Acrobat is actually re-structuring the Illustrators' pdf internal file structure and optimizing it?
Perhaps Dov can shed some light here...