How can I make a reasonably sized PDF for printing?

[Karina]

Hi, I make PDF’s (X1a:2003) to print artwork. Typically, a PDF I create for an A3 poster is about 12 MB. The printing company says this is extremely big, they expect something in the kb range. Is there a way to make the PDF files smaller, yet retain optimal quality? 
 

I don’t know if this is relevant, but the printing company normally request PDF X1a:2001 files, but Affinity doesn’t support this older PDF format. 
 

Thank you very much for your help!
Karina

[Callum]

Hi Karina,

I wouldn't say this is particularly big for a PDF file especially if it contains many images etc. If possible could you provide the file in question so I can best advise you on this?

Thanks

C

[Fixx]

A normal press quality A3 PDF with full image should be somewhere 3-8 MB. Affinity definitely makes them bigger. Possibly there is less image compression applied than in other tools?

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[Karina]

Ok, thank you all! Sorry for my late reply, as it took four days before I got any feedback I wasn’t really expecting an answer anymore. The dpi is 300, and this is recommend by the printing companies I use, so I don’t think I should change that. Plus I use just one (scanned watercolour) artwork per poster.  Apparently this is an Affinity thing if I understand correctly, I tried all kinds of setting on this does not make a difference at all in file size. The printing company was a but puzzled and didn’t know how to make the files smaller. Now I just upload the posters one by one to the printing company instead of making one mega file, which works fine. I guess I’ll have to work around this issue until it is fixed. 

[wonderings]

I think you should be looking at a different printer. 12mb being a large file?? I would be worried about any art/poster print being in the kb's. Without seeing the artwork, 12mb does not sound out of line or abnormal. I would not be looking at reducing any quality or DPI to reduce the PDF file size down from 12mb. That really is insane as those sizes are now small and can easily be sent in an email as attachment. 

[Karina]

Ok, good to know! I tend to print many posters at the same time, and they had to be in one (huge) file of sometimes 180 MB. Couldn’t sent that via mail and even Wetransfer didn’t manage. Thank god you can now upload individual poster designs, haven’t heard them complaining since! 

[wonderings]

Just now, Karina said:

Ok, good to know! I tend to print many posters at the same time, and they had to be in one (huge) file of sometimes 180 MB. Couldn’t sent that via mail and even Wetransfer didn’t manage. Thank god you can now upload individual poster designs, haven’t heard them complaining since! 

180mb while a somewhat large file should be easily handled by WeTransfer. The free transfer from WeTransfer has a maximum size of 2 gigs. 

I regularly get files that size or larger. Never something I would complain about.

[Alfred]

12 minutes ago, Karina said:

The dpi is 300, and this is recommend by the printing companies I use

You really don’t need 300 DPI or more for an image of that size unless it’s something like a map that may be subject to very close inspection.

At 200 DPI you will be unable to discern individual pixels when viewing an A3 poster from a distance of 18 inches (45 cm) or more. At 150 DPI you can view that poster from as little as 2 ft (60 cm) away and still be unable to distinguish between pixels.

[Karina]

27 minutes ago, wonderings said:

180mb while a somewhat large file should be easily handled by WeTransfer. The free transfer from WeTransfer has a maximum size of 2 gigs. 

I regularly get files that size or larger. Never something I would complain about.

Thanks for your reply. The problem for me was as well that our wifi couldn’t manage sending files that big via wetransfer unfortunately. I live in an apartment in the city, so yeah. A bit of a wifi war now that everyone is working from home... 

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[thomaso]

1 hour ago, Lagarto said:

It is a mystery what causes this difference

Isn't a (or the) reason the different JPEG compression, its algorithm in general but also certain (differing?) quality settings?

[thomaso]

1 hour ago, Lagarto said:

I noticed that if the image is cropped with Publisher Vector Crop Tool (a notoriously problematic tool), the file size blows up to this 13,509KB, and when looked inside, the uncropped image size seems to have been upsampled (become larger than original).

With a quick test I don't get remarkable differences. Might it occur in the Windows version only?

Here 3 PDFs (v.1.7) of an image clipped via – white rectangle, – picture frame, – croptool:  427 – 415 – 414  kB 
I assume the slightly different fie sizes are caused by not clipping exactly the same image details.

v184 img rect.pdf
v184 img pictfrm.pdf
v184 img croptool.pdf

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[thomaso]

2 minutes ago, Lagarto said:

specify practically identical export settings (APub: Allow JPEG, 98 quality, ID: JPEG Automatic, (JPEG), "Maximum" quality)

... not to forget profile embedding on/off.

When you open the PDFs in Acrobat and choose Save as... > Optimized ... then you have a button for file structure data sizes (~'memory usage'). Might it enlighten with any differences for various PDFs?

 

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[thomaso]

8 hours ago, Lagarto said:

I cannot say as I have not code at hand. What I meant to say is that if I, as a user, specify practically identical export settings (APub: Allow JPEG, 98 quality, ID: Automatic (JPEG), "Maximum" quality), using virtually the same PDF/X method at default values

1.) I am quite sure the different pdf file sizes are related to different compression qualities: while we can set "98%" for APub we have for ID no number but "Maximum" only.

In my opinion 100 % (and even 98) is not very practical for print files if you consider that a quality of 100 – 90 % does not show visually noticable differences but does result in remarkable different file sizes. (roughly spoken ~50% size reduction) (see this comparisons of J.Friedl, formerly Adobe)

With default export settings (PDF/X-4 – "Maximum" / "98%") I get similar file size differences as you: APub pdfs tend to be almost twice the size of ID pdfs.
It becomes interesting when I use different qualities on APub exports, then it appears ID and APub produce the same size if APub is set around 91% quality (not 98 or 100 % !):

I don't get your differences with APub exports when using the croptool, here the picture frame result is even slightly larger (which may have various reasons, e.g. imprecise manual cropping and or Finder size rounding in macOS).

2.) Another interesting spot occurs when I export the JPGs from the exported PDFs (via Acrobat tools > document > image export). Then the smaller ID PDF creates a JPG which is ~ 25 % larger than those from APub. And even the two quite different APub PDFs (12,5 MB and 7 MB) result in the same exported JPG size:

(exported from Acrobat with "Maximum", size ~4900 px width / the original JPG used in the layouts is 5100 px, 8 MB)
So, the Adobe term "Maximum" for JPG quality obviously can have different values and processes or meanings.

3.) just FYI a comparison of Acrobat's info about the file structure data sizes:  ID pdf 7 MB  /  APub pdf 12,5 MB:

  

Note: Acrobat mentions for APub's PDF 2.6 MB for "Color Spaces" ("Farbräume") – but not for the ID pdf.
Both PDFs were exported with default PDF/X-4 and will have the profile of the layout image embedded, which is Adobe RGB (from Lightroom). The Acrobat preflight gives slightly different info about the profile in both PDFs, e.g. for creators, I assume because of different PDF libraries used by ID vs. APub for exports.

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[thomaso]

3 hours ago, Lagarto said:

...so to achieve nearly the same file size as InDesign (...), i would need to export with 0 JPG quality when using Affinity Publisher. 

(...) the size of the embedded image in quality 0 file is  188KB:

...while the file size is 1,521KB (...) I wonder where Publisher uses the extra 1,333KB when it exports this file.

(sorry for cropping your post, I did to focus)
I suppose the additional 1,333 kB are caused by an embedded output intent profile for X-1.
Note you can't deselect the embed checkbox (though resources get converted and don't get their profile embedded):

Accordingly Acrobat shows a "Document Overhead" of 1.7 MB, for both PDFs:
ID vs. APub:

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Note above the different image data sizes, resulting from the initially 32 kB jpg used for this test (1095 px width, exported from AP in cmyk / q0 / without profile). I assume the initial image quality of 0 gets recompressed on PDF export according to my settings (max / 98). Here it appears odd that both apps increase the inital 32 kB up to 80 (id) and 150 (apub) which is roughly 3x and 5x of the size, although there were no pixels to "improve" in this jaggy, low res 32 kB jpg.

The exported PDF size is shown in the Finder for both as the same with 1.9 MB:

 

[thomaso]

1 hour ago, Lagarto said:

With this image (sRGB TIFF) and this kind of crop, the negative effect of crop tool / rectangle mask could be reproduced also on macOS version of Publisher (latest release version).

Strange. I did not get remarkable differences for a JPG (Adobe RGB) with different ways of cropping in APub, mentioned here and here.

– Would that mean the placed image file type (TIFF) is influencing this?
Just guessing: Can you detect if the compressing method for the TIFF is the same in both exported PDFs? Maybe zip versus jpg?

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