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Nick Walker
Known Participant
May 25, 2023
질문

InDesign Compression Rates - PDF smaller then anticipated

  • May 25, 2023
  • 5 답변들
  • 4247 조회

I am creating a PDF image borchure in INDesign from 50 jpeg images that were saved in Photoshop from 16 Bit Tiff files to 12 compression jpegs. The total folder size for the 50 jpeg images is 457.7 meg.

 

InDesign export using no compression results in a 1.6GB PDF (optimise for fast web view off).

INDesign export using jpeg maximum compression renders an 85 meg PDF (optimise for fast web view off).

 

Please see attcahed inDesign Export screen grabs for General, NO compression and jpeg max tried.

 

An InDesign ZIP version is around 645 meg but the print company wont recognise a ZIP compression version PDF.

 

Is there a higher qiality jpeg compression setting that I am missing that will save a PDF with less compression? 

 

I had hoped that InDesign would leave the 12 compression jpegs uncompressed and create PDF of a similar size as the folder of 50 images at approx 457 meg, certainly more then 85 meg.

 

 

이 주제는 답변이 닫혔습니다.

5 답변

rob day
Community Expert
rob dayCommunity Expert
Community Expert
June 2, 2023

I had hoped that InDesign would leave the 12 compression jpegs uncompressed

 

Hi @Nick Walker , If you set an Export Compression method InDesign exports the placed images’ pixels using the rules you’ve set—there is no advantage in going to the extra steps of converting your 16-bit TIFFs to JPEGs in Photoshop. A placed JPEG exported with JPEG compression is going to be double compressed—the JPEG artifacts from the InDesign export compression will be added to the existing JPEG artifacts of the initial Photoshop compression.

rob day
Community Expert
rob dayCommunity Expert
Community Expert
June 2, 2023

Hi @Nick Walker , Also, you can use AcrobatPro’s Object Inspector to see that the initial compression of a placed JPEG is not used. Here I’ve placed a JPEG saved at maximum quality compression out of Photoshop—the placed JPEG has a file size of 4.5MB:

 

 

If  I Export to the default PDF/X-4 preset with all compression turned off, the JPEG’s initial compression is ignored (its compression artifacts would still exist), and no new compression is applied on the export, so the PDF is 8x larger at 32.3MB:

 

 

 

If I place the same file as a layered, 16-bit .PSD, the image gets flattened and converted to 8-bit even though I have compression turned off. In this case the original 16-bit file is 155MB, and the PDF is 42.9 MB because all image formats get converted to 8-bit and flattened on export even when compression is turned off:

 

Peter Spier
Community Expert
Peter SpierCommunity Expert
Community Expert
May 25, 2023

THere are two places where InDesing might be throwing away data in the settings you show. First is in the downsampling -- as Bevi mentioned, effective ppi is key here. If these were extremely high resolution images to stasrt, or were scaled down in InDesign there could be downsampling.

Second place is you have the box to checked to crop data to frames. If yoou cropped the images in InDesign the areas outside the frames will be discarded with this setting, but no damage to the retained image data should occur other than that realted to the other downsampling, if any.

Bevi Chagnon - PubCom.com
Bevi Chagnon - PubCom.com
Legend
May 25, 2023
quote

I am creating a PDF image borchure in INDesign from 50 jpeg images that were saved in Photoshop from 16 Bit Tiff files to 12 compression jpegs.

By @Nick Walker

 

@Nick Walker, can you expand on this part of your workflow? It's confusing and I see you're using 3 different file formats: JPEG, TIFF, and JPEG again.

 

What file types are you opening in Photoshop?

While working on the photo in Photoshop, what file format are you saving the project in, PSD or JPEG?

And when you're done correcting and adjusting the photo on Photoshop, what file format are you saving the final file in, TIFF or JPEG or PDD?

 

 

|    Bevi Chagnon   |  Designer, Trainer, & Technologist for Accessible Documents ||    PubCom |    Classes & Books for Accessible InDesign, PDFs & MS Office |
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Nick Walker작성자
Known Participant
May 25, 2023

Hi Bevi,

 

It's kind of you to reply in such a comprehensive manner. I understand digital but I am new to the world of PDF software and don't understand why InDesigns algorithms throw away such much data compared to resaving the same files in Photoshop.  For example I jave just performed the following tests: 

1. Photoshop - 50 images saved directly from 16 bit Tiff files totals 475.7 meg

2. Photoshop - same 50 jpeg 12 compression images images 'recompressed' in Photoshop aklso using 12 compression files total 217 meg.

3. InDesign jpeg Bicubic Maximum, using the same 50 images that were saved directly from Photoshop 16 bit Tiff (not recompressed jpegs) results a total of 85 meg PDF

 

I have been scanning images and digital camera files since thge late 90s in my capacity as a full timne professional sports photographer - dug very deep on the technical aspects of digital photography and colour management. I avoid jpegs like the plague, other than when forced to use them. My image files start off as RAW files are saved as 16 Bit Tiffs in Pro Photo RGB archived as master files in my library, saved to whatever format the client requests.

 

I fully understand that recompressing a jpeg is not optimal, although a 12 compression jpeg made directly from a 16 Bit Tiff is very difficult to tell apart if recompressed only one more time using 12 compression for less critical repro. If I was still printing my own work on a professional wide format printer I would leave the original archived file as a 16 Bit Tiff Pro Photo RGB, however, I am sending a 50 image PDF to outside printers. The first PDF I sent using non compression was 1.6GB (almost 3 hours to send on our village broadband!). I received the brochures back last week and I am very pleased to say that the colour accuracy is eceptionally good for the price - I soft proofed and compensated using their iic profile.

 

My queerie is about InDesigns compression rates which throw a lot of data using JPEG maximum comaperd to photoshops 12 compression. This might be because there is a setting I have incorrectly set. 

 

In future I will import Tiff files into INDesign and try the jpeg maximum setting as Test Screen Name has suggested in a previous post to see what file PDF size INDesign generates.

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Nick Walker작성자
Known Participant
May 25, 2023

 

 

Please ignore the previous post sent in error with loads of typos!!! I hooe that this reads a little bit better.

 

It's kind of you to reply in such a comprehensive manner. I understand digital but I am new to the world of PDF software and don't understand why InDesigns algorithms throw away such much data compared to resaving the same files in Photoshop.  For example I have just performed the following tests: 

1. Photoshop - 50 images saved directly from 16 bit Tiff files totals 475.7 meg

2. Photoshop - same 50 jpeg 12 compression images images 'recompressed' in Photoshop also using 12 compression files total 217 meg.

3. InDesign jpeg Bicubic Maximum, using the same 50 images that were saved directly from Photoshop 16 bit Tiff (not recompressed jpegs) results a total of 85 meg PDF

 

I have been scanning images and digital camera files since the late 90s in my capacity as a full time professional sports photographer - dug very deep on the technical aspects of digital photography and colour management. I avoid jpegs like the plague, other than when forced to use them. My camera images are captured as RAW files, then saved in Lightroom as 16 Bit Tiffs in Pro Photo RGB and archived as master files in my library, only copies are re-saved to whatever format the client requests.

 

I fully understand that recompressing a jpeg is not optimal, although a 12 compression jpeg made directly from a 16 Bit Tiff is very difficult to tell apart if recompressed only one more time using 12 compression for less critical repro. If I was still printing my own work on a professional wide format printer I would leave the original archived file as a 16 Bit Tiff Pro Photo RGB, however, I am sending a 50 image PDF to outside printers. The first PDF I sent using non compression was 1.6GB (almost 3 hours to send on our village broadband!). I received the brochures back last week and I am very pleased to say that the colour accuracy is exceptionally good for the price - I soft proofed and compensated using their iic profile.

 

My query is about InDesigns compression rates which throw a lot of data using JPEG maximum compared to photoshops 12 compression. This might be because there is a setting I have incorrectly set. 

 

In future I will import Tiff files into INDesign and try the jpeg maximum setting as Test Screen Name has suggested in a previous post to see what file PDF size INDesign generates.

Bevi Chagnon - PubCom.com
Bevi Chagnon - PubCom.com
Legend
May 25, 2023

Hi @Nick Walker, I'm trying to follow your workflow and sort out where the solution lies. It appears that the photos are being compressed 2 or more times in your workflow and that's not ideal for quality graphics.

 

And it sounds like you're also concerned about the final size of the file submitted to your print shop, correct?

 

Some clarifications (for everyone who finds this discussion now and in the future):

  • The JPEG file format is a lossy compression format. That means each time a file is saved as a JPEG/JPG file, it gets compressed again and data is lost. For a photo, this data loss causes fuzziness/blurriness, wierd colors, color shift, loss of detail and clairty, and halo artifacts where hi-contrast pixels meet.
  • The ZIP file format is also a compression format, but it's considered loss-less, that is the data is not corrupted. That's the theory, at least!
  • If the original photos were JPEGs that were opened in Photoshop, they've already been compressed once, before the layout is created in InDesign and export to PDF.
  • If the InDesign layout is exported using the preset PDF settings, the photos will be embeded as JPEGs in the PDF — and compressed again. Selecting the option to not compress the images embeds the original file format and its full resolution into the PDF.
  • In today's world, it's tough to avoid working with JPEGs at the start of the project: your stock photos and camera shots are usually JPEGs. But you want to minimize how many other times you'll JPEG the same data to prevent it from being over-corrupted in the end.

 

First, to better help you, what type of PDF are you trying to make from InDesign:  a press-quality PDF? PDF/X? Print PDF?

And what final resolution do you want the photos to have in that final PDF you submit to a printer — 300? 400? 600?  Your print shop determines the ideal resolution needed for the type of print technology, paper, quality, etc.

 

Second, what is the effective resolution (number of pixels) of the photos in the InDesign layout file? That's the most critical number in the workflow. Note that as a photo is enlarged in the layout, the effective resolution is reduced, and as you scale down a photo it's effective resolution increases.

 

Third, what are the compression settings in your PDF export options? The default setting is "Bicubic downsampling to 300 ppi for images above 450 ppi."  If your print shop only wants 300, this setting needlessly bloats your file, and with 50 photos in your project, that will add a significant amount of data to the PDF.

 

Knowing these three factors can help you have the ideal resolution in the final PDF and reduce the need to compress the photos again. It helps you find the "sweet spot." And hopefully get the PDF file size down to something your print shop can use.

 

|    Bevi Chagnon   |  Designer, Trainer, & Technologist for Accessible Documents ||    PubCom |    Classes & Books for Accessible InDesign, PDFs & MS Office |
T
Test Screen Name
Legend
May 25, 2023

InDesign will uncompress and recompress the JPEG. Since each repeat will damage it more, abolish JPEG from the workflow and stick with TIFF, using best quality JPEG option in Export. 

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    Nick Walker작성자
    Known Participant
    May 25, 2023

    HI,

     

    Thanks for your reply. I am not new to digital imaging but definitley a newbie to InDesign. I will take your advice and import Tiff files in future. 

     

    An extract to the reply below I sent to Bevi

     

    1. Photoshop - 50 images saved directly from 16 bit Tiff files totals 475.7 meg

    2. Photoshop - same 50 jpeg 12 compression images 'recompressed' in Photoshop also using 12 compression files total 217 meg.

    3. InDesign jpeg Bicubic Maximum, using the same 50 images that were saved directly from Photoshop 16 bit Tiff (not recompressed jpegs) results a total of 85 meg PDF

     

    My queerie is about InDesigns compression rates which throw away a lot of data using JPEG maximum comaperd to photoshops 12 compression. This might be because there is a setting I have incorrectly set. 

     

    In future I will import Tiff files into INDesign and try the jpeg maximum setting as Test Screen Name has suggested in a previous post to see what file PDF size INDesign generates

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