I’m working on a 12-month digital planner that includes raster images on every page. This is a product file, so maintaining a consistent and optimized file size is important.Last month, using Save As Other → Optimized PDF, I was able to reduce the file to under 5 MB, while still maintaining: All hyperlinks Acceptable image quality Full functionality This surprised me (in a good way), since the file contains raster images on every page.This month, however, I cannot achieve the same file size — even though: The page count is the same The exact same images are being used The layout structure is the same No new assets have been introduced Here are my Optimized PDF settings:Compatibility Make compatible with: Acrobat 10.0 and later Images Downsample to 150 ppi for images above 225 ppi JPEG compression: Medium quality Fonts Subset all embedded fonts Discard User Data Discard document information and metadata Discard private data of other applications Despite using the same workflow and settings, the file size is noticeably larger this month.My questions: Why would identical content and identical optimization settings produce different file sizes? Could Acrobat be retaining hidden objects, incremental save data, or internal versioning that affects final size? Is there something additional I should be clearing (object-level compression, transparency data, hidden layers, etc.)? Is there a more reliable workflow for ensuring repeatable file size results? I’m trying to create a consistent, repeatable process for monthly releases of this product.Any insight would be greatly appreciated. Thank you!

Participant

Question

Cannot Replicate Previous Optimized PDF File Size (Same Pages, Same Images)

Forum|Forum|1 month ago
February 27, 2026
2 replies
45 views

I’m working on a 12-month digital planner that includes raster images on every page. This is a product file, so maintaining a consistent and optimized file size is important.

Last month, using Save As Other → Optimized PDF, I was able to reduce the file to under 5 MB, while still maintaining:

All hyperlinks
Acceptable image quality
Full functionality

This surprised me (in a good way), since the file contains raster images on every page.

This month, however, I cannot achieve the same file size — even though:

The page count is the same
The exact same images are being used
The layout structure is the same
No new assets have been introduced

Here are my Optimized PDF settings:

Compatibility

Make compatible with: Acrobat 10.0 and later

Images

Downsample to 150 ppi for images above 225 ppi
JPEG compression: Medium quality

Fonts

Subset all embedded fonts

Discard User Data

Discard document information and metadata
Discard private data of other applications

Despite using the same workflow and settings, the file size is noticeably larger this month.

My questions:

Why would identical content and identical optimization settings produce different file sizes?
Could Acrobat be retaining hidden objects, incremental save data, or internal versioning that affects final size?
Is there something additional I should be clearing (object-level compression, transparency data, hidden layers, etc.)?
Is there a more reliable workflow for ensuring repeatable file size results?

I’m trying to create a consistent, repeatable process for monthly releases of this product.

Any insight would be greatly appreciated. Thank you!

Dave Creamer of IDEAS

Community Expert

My usual image settings for downsampling is to downsample anything above my target resolution. For example, downsample to 150 ppi for anything above 150 ppi. My thought is if I’m willing to accept 150, why wait for an image to over 225?

David Creamer: Community Expert (ACI and ACE 1995-2023)

AnandSri

Legend

Hello @Diane32394960k6md

I hope you are doing well, and thank you for reaching out and sharing detailed information.

Why identical content can produce different file sizes?

1. PDF Optimizer works on what’s actually inside the PDF, not just what’s visible
Acrobat compresses existing PDF objects. Two PDFs that look the same can contain different internal structures (duplicate image objects, unused resources, transparency data, thumbnails, or cached objects). Use Audit space usage to see what’s really consuming space.

2. Incremental saves and document history matter
PDFs can retain prior revisions and unused objects from earlier edits. Acrobat removes many of these during optimization, but results can still vary depending on how the PDF was created or edited before optimization. Saving optimized PDFs as new files, not overwriting originals, to avoid retained structure and history.

3. Image handling can differ even with the same assets
PDF Optimizer downsamples and compresses images based on how they’re embedded. The same image file reused in different ways (for example, duplicated vs. referenced once) can change results. The image down sampling and compression are applied per object, not per “asset”.

4. Transparency and object data can inflate the size
If transparency, hidden layers, thumbnails, or unused objects exist, they add size. Transparency, Discard Objects, and Clean Up panels are important for reducing size consistently.

Suggestions:

1. Run Audit space usage: This shows exactly which elements (images, fonts, transparency, metadata, etc.) are taking space.

Menu > Save As Other > Optimized PDF > Audit space usage.

2. Review additional Optimizer panels: Even if Images/Fonts/Discard User Data match, also review:

Transparency (flatten if present)
Discard Objects (thumbnails, form data, unused objects)
Clean Up (remove invalid or redundant structure, optimize for fast web view)

Let us know if that helps.

Regards,

Anand Sri.

D

Diane32394960k6mdAuthor

Participant

Thank you for the in-depth reply. I really appreciate the time you took to explain these possibilities.

I’ll be revisiting this project soon and plan to review the points you mentioned more carefully. I think #3 may be especially relevant to my situation.

In this planner, there is a Daily Notes page that gets repeated throughout the document (365 times). My workflow for inserting those pages hasn’t always been consistent. Sometimes I copy the page directly from the original Daily Notes PDF and paste it repeatedly into the planner. Other times, I insert the page once into the planner and then copy and paste it within the planner itself until I reach the full set of 365 pages.

There are actually two versions of this planner:

A base version, where users insert the Daily Notes template themselves as needed.
An integrated version, where the Daily Notes page is already included throughout the planner.

Based on your explanation, I’m wondering if the different ways I’ve been inserting or duplicating that page might affect how Acrobat handles the underlying page objects or resources, which could explain the variation in file size.

I’ll experiment with this more when I return to the file. Thanks again for the helpful insight.

AnandSri

Legend

Hello @Diane32394960k6md

I hope you are doing well, and thank you for the detailed information.

You’re right, the way the Daily Notes page is inserted can impact file size.

Key points:

When a page is copied in from another PDF, Acrobat may embed its images and other resources again.
If the page is inserted once and then duplicated within the same document, Acrobat is more likely to reuse shared objects.
With a page repeated 365 times, small differences in resource handling can add up quickly.

Recommendation:

Insert the Daily Notes page once
Duplicate it internally to reach the full page count
Run Optimize PDF only after the document structure is finalized

Mixing different insertion methods in the same file can result in identical‑looking pages that aren’t technically identical, which explains the file size variation.

I hope this helps, and I will wait for your response with the experiment results.

Regards,

Anand Sri.

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