InDesign Compression Rates - PDF smaller then anticipated

Report · May 25, 2023

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.

Report · 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.

Report · 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

Report · 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.

Report · May 25, 2023

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?

Report · 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.

Report · 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.

Report · May 25, 2023

In my previous posts iic is another typo - I meant icc profile!

Report · May 25, 2023

Hi Nick,

Pleasure to meet fellow photographer.

InDesign actually doesn't do a thing to photos: it's the PDF export utility that controls the resolution, file size, color fidelity, compression, etc. This built-in utility is written by Adobe's Acrobat programmers, which is probably a different group from those that program Photoshop.

These settings control the output of the PDF from InDesign:

The Effective Resolution of each photo as listed in the lower section of InDesign's Links panel. This is the ppi data that will be sent to the PDF when exported. It's measured after you've enlarged or shrinked the photo in the INDD layout. So your original ppi resolution from Lightroom/Photoshop doesn't factor into the equation once you're in InDesign. Send too much data to the PDF and the file will be bloated with extraneous bytes of data.

A demonstration:

Original full-page photo shows an Effective Resolution of 560 ppi. That's too much pixel data for most printers that usually want 300 – 400 ppi.

Full page: Effective PPI Resolution.

Same photo but scaled smaller in the InDesign layout shows an Effective of 1116 ppi — an immense overload of pixel data for any type of printing.

Quater page: Effective PPI Resolution.

Embedded ICC profiles adds bytes of data to the PDF file.
PDF Export Settings:
- The Compression settings — Resolution. 300 ppi, 400 ppi, etc. The higher the resolution, the bigger the PDF file. The export utility will downsample the Effective Resolution (above) to whatever you set, 300 or 400 ppi. So the second example @1116 ppi can end up as 400 ppi in the PDF. This minimizes the data to only what's needed to print the PDF at the print shop.You should ask your print shop what resolution they want.
- Compression. Auto JPEG is the standard, but you can try any of the others (except ZIP), including the newest JPEG 2000 which is supposed to retain critical color and fidelity. Make sure your print shop can handle the alternate formats.
- Image Quality. I think you'll want Maximum quality for your professional photography work. But you can also dumb it down to High and get very satisfactory results.

If I was promoting my professional photography like you, here's the workflow I'd use:

Open the RAW photo in Lightroom/Photoshop.
Edit the image however I want. Embed the ICC profile.
Save the final mastered image in the native Photoshop PSD or Lightroom file format. Notice how there's no need to convert my source (Lightroom/Photoshop) files at this stage.
Place the native PSD file into InDesign.
Resize the photo in my InDesign layout, making sure that the Effective PPI of each photo never goes lower than 300 ppi. I actually aim for 400 ppi because I've discovered that many of my print shops have now upgraded their printing tech and can create more rich appearance from 400 than from 300, especially if they use Stochastic screening during prepress. But if the Effective ppi in InDesign is higher, don't fret because all photos will be "sanitized" to whatever my PDF export settings are.
File / Export to PDF with these settings:
- Press Quality with Compatibility at Acrobat 8 (PDF 1.7).
  
  No layers, no interactive stuff, just check the basics.
- Compression: PPI set to 400. I've had good success with Automatic JPEG and Maximum, but adjust to fit your needs.
  
  Make sure to corp the image data to whatever you fit inside InDesign's graphic frames. The print PDF doesn't need the cropped-out data.
- Output: These are my preferred settings, but adjust then to fit your needs. Also, we use US Sheetfed Coated here in the US for the printer/destination color system, but your print shop might use GRACol or FOGRA. Check with him.

See if this strategy helps get the file size down to something more manageable.

And as a last resort, you can always copy the file onto a USB drive and deliver it in person to the print shop. Might be a nice excuse for a day trip...Motorbike, your sweetie on the back, picnic basket filled with Chardonnay, loaf of bread and charcuterie spread...and the Nikon of course!

The day trip could take less time than your local broadband <grin>.

Report · Jun 02, 2023

Hi Bev,

Sorry for the late reply. Thank you for your informative reply.

I have always archived my images at 300 ppi, interesting that you have found some print shops using newer printers benefit from 400 ppi.

P.S. Although ink jet printers are different beasts I know from my own in depth tests conducted many years ago with certain Epson pro printers there was a slight advantage in fine rendering to send 360 ppi or 720 ppi image files (rather than 300 ppi) to the printer (dependent on the file and print size combination), however, this is another topic altogether.

Report · Jun 02, 2023

Most printers can print 1200 dpi. Offset printers even 2400 dpi. They just ask for 300 dpi because it has been te standard for 20 years and the files are alot smaller and easier to progress. You should also change the standard from "none" to "PDF/X-4:2010" this is a print standard and adds the profile to the PDF so the printer knows to what profile you converted.

Report · 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.

Report · Jun 02, 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.

Report · Jun 02, 2023

One other thing. I think this partly comes from assuming that the maximum JPEG quality in Photoshop is the same as the maximum JPEG quality in InDesign PDF export. A natural assumption, but no. What a lot of people do not realise about JPEG is that compression isn't a simple quality scale. There are a LOT of choices that an app makes, about how to chop up your colours, whether to convert RGB to HLS, whether to subsample in the JPEG, and other things. This is considered too complicated for us to worry about, so apps often just have a "quality scale" but each point on the scale is actually making choices about colour conversions, chopping, subsampling and more. The tables in Photoshop were revised a few years ago (they used to run from 1 to 10). The tables in PDF export were NOT revised. So there is no match between them. (I happen to know this because I did a lot of quality and compression tests over 20 years ago).

Report · Jun 02, 2023

This is true, you don't have to convert to jpegs beforehand. Also the compression on maximum is no problem as long as you don't edit the image anymore after. Which you probably won't sinvlce it's in a PDF

Tim De Vos
Colourmanagement specialist
DIE KEURE PRINTING

Report · Jun 02, 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: