My lowres pdf is 300mb, normally it should be about 10 mb max.

[hanneke61]

I want to create a PDF with the smallest file size. However, it will be 300 MB in size, while normally it is a maximum of 10 MB. I use large images, more than 600 dpi, but they should be automatically reduced in size with a low-res PDF. Is there a setting that is preventing it from working as I would expect? I already read something about downsampling, but I can't find that when I export.
Can anyone help me further?

[rob day]

Hi @hanneke61 , Can you show a screen cpture of your Export dialog’s Compression tab?

[hanneke61]

 

[Willi Adelberger]

Don't include page thumbnails into the PDF. 

[hanneke61]

Thank you, I tried this but it did not help

[James Gifford—NitroPress]

How many pages is your document, and how many images does it contain?

[Eugene Tyson]

If a document is not behaving well then try 

File>Export 

Choose IDML

Open the IDML in InDesign
Save the file as a new InDesign file with a new name
See if the issue persists.

[hanneke61]

Thanks for the suggestion. I tried this but it didn't help. The PDF was the same size again. Then I created a new document and dragged all the pages into it. This also gave an equally large file.
I make a similar booklet every year, I exported last year's booklet and that worked well, it was 5 MB.
Is there anything else I can try?

[hanneke61]

I also exported different pages to see if there would be one image that causes the problem. I exported page 1-10, that gave 59 mb, then I exported one spread 11-12, that gave 1,5 mb. So also not here is the issue

[James Gifford—NitroPress]

You haven't really answered the basic question here: just how large are these images? "600dpi" means nothing in absolute size. What are their pixel dimensions and source file sizes? What are the layout/page sizes? And how many of them do you have in this document?

[hanneke61]

there are many images, some used several times. The  absolute sizes are from 300 dp - 1800 dpi. 
There are also ai images. Thera are 76 pages- size a5
But I think the effective pixelsize should not matter when I create a lowres pdf, because every image should be resized to 72 dpi. Am I wrong? And also previous year I did it the same way.  

I have reduced some of the images considerably, but it remains at 295 MB.
These are the package maps from previous and from this year. 

A diffence is the size of the illustrator images. I don't know why, but they are very large. This simple one for example is 25 mb:

[James Gifford—NitroPress]

Stating an images DPI or PPI is not a useful figure, despite it being commonly tossed around. You can have a one-inch by one-inch image that's 300 pixels by 300 pixels that is an "1800ppi image" — that figure is just an arbitrary number assigned by Photoshop or the like to indicate what print or display size the image is meant to be.

The important figures are the actual pixel dimensions of the image — such as 900 x 600, or 3000 x 6000, or such, and that will be more or less proportional to the actual source file size (1 meg, 10 megs, etc.)

I suspect you are using enormous and probably oversized image files and not taking the right steps for them to be downsampled to a reasonable export size and PPI. But an answer has to start with —

• Some representative image sizes, in pixel height and width;
• Some representative image sizes, in source file size of kb or Mb;
• A total of how many images you are using in this document.

As for AI images, there are many reasons they can be large (too large), such as embedding high-resolution raster (photo) images in them.

I think all of the images you're using need to be reviewed at a technical/format/size level to get you to a usefully small PDF.

[hanneke61]

thank you for your answer. I will check all images for size in relation to final formats. but what I don't understand is that last year's folder with images is the same size as this year's, but that the differences in PDF format are so great. like the image in my previous post. And I also don't understand why a simple AI image is already so large in my previous message. there is no raster image in it. not even in hidden layers or anything.

[James Gifford—NitroPress]

There is simply no way to resolve this with nothing but general information. All due politeness, you are continuing to misunderstand some very basic questions and answer with "nothing's changed" or "the files are 600 dpi" and so forth, which indicates you may be overlooking some highly relevant technical problems here.

We know absolutely nothing about your project or its elements, this year or any prior year, and need very specific information to help pinpoint why you might not be getting optimal (or at least expected) results.

[rob day]

But I think the effective pixelsize should not matter when I create a lowres pdf, because every image should be resized to 72 dpi. Am I wrong? And also previous year I did it the same way.

Looks like something else is causing the excessive file size–your compression setting would not create a 300MB PDF from the images alone. Sounds like it could be the Photoshop ancestor metadata bug—see this thread:

https://community.adobe.com/t5/indesign-discussions/is-there-a-script-to-clear-indesign-metadata-red...

Also you can run an audit of the PDF in AcrobatPro — Optimize PDF>Advanced Optimization>Audit space usage... —that will tell you what percentage of the files size is allocated to images:

[hanneke61]

I did what you suggested and I see 88% is from schaduwgegevens. 
what can I make of that?

[rob day]

Are you using a lot of transparency effects? What happens if you Export a Print PDF to an sRGB Destination?

[Eugene Tyson]

We don't know either 😄 - you'd have to share images/files with us to investigate. 

See this thread on how to audit your file and see what's causing the extra clump of data that is making it so large
https://community.adobe.com/t5/photoshop-ecosystem-discussions/why-do-some-pdf-s-come-out-at-massive...

If it's vector images then they won't be compressed, as they are vectors not rasters.

If you don't need them as vector, as they are online, you could try saving them as PSD or TIFF and relink them in InDesign
https://creativepro.com/relink-from-one-image-file-type-to-another/#:~:text=But%20even%20cooler%2C%2....

See if that helps.

If the vector images are large then the PDF will be too.

[leo.r]

I also exported different pages to see if there would be one image that causes the problem. I exported page 1-10, that gave 59 mb, then I exported one spread 11-12, that gave 1,5 mb. So also not here is the issue

By @hanneke61

Ok you said you have 76 pages in total, so exporting 12 pages doesn't prove anything so far.

Try to export your file in 7 chunks (1-10, 11-20 etc.) and see which PDF is particularly large. Then you can isolate the issue to a specific page (or pages).

[hanneke61]

The problem was in the vector files. I still don't really understand how that happened because they were simple drawings.
Also, I don't know what it means that the PDF audit indicated that 88% of the space was occupied by shadow data. Anyway, I replaced all the vector files with JPFs and now the size is 5 MB, as I would expect.
Thanks for your thoughts!

[leo.r]

The problem was in the vector files. I still don't really understand how that happened because they were simple drawings.
Also, I don't know what it means that the PDF audit indicated that 88% of the space was occupied by shadow data.

By @hanneke61

If vector files have certain transparency areas (including shadows), they can end up being split into thousands (or tens of thousands or more) of tiny images. The PDF size then  can increase enormously, like in your case.

If you still have your old huge PDF, you can open it in Acrobat, open the Preflight panel and run the "List page objects grouped by type of object" profile. Will it show a huge number of small images?

(My UI is in Spanish as part of an experiment of immersive Spanish learning).

[hanneke61]

Is this what you mean? 

[leo.r]

Yes. The profile you ran only lists transparent objects but you can already see you have nearly 5000 of them. And how many links in total do you have in your document? I'm sure it's much less than that.

If you run the profile I mentioned - List page objects grouped by type of object - it will list all images (not only transparent objects), which might as well show hundreds more of additional images.

[hanneke61]

Yes, I see! Now I understand that this file was 295 mb!  I am so glad that I now understand what happened. 
Is there a way to use illustrator with shadows and transparancy, without this problem? Maybe export it on a certain way?
If I show a design to my client, I prefer to use vector in stead of pixel images, because then I can more easy make changes in the illustrations.

[rob day]

If I show a design to my client, I prefer to use vector in stead of pixel images, because then I can more easy make changes in the illustrations.

Is there a reason for Exporting an Interactive PDF? Does the final PDF require interactive elements or are you showing the client a layout that will go to print?