How can I make my PDF file size smaller without losing quality?

Open your PDF in Acrobat and go to File > Save as Other > Optimized PDF. In the 'Images' section, set color/grayscale images to about 150 dpi and monochrome to 300 dpi. Choose 'JPEG quality Medium/High' (around 85%) for images. In the 'Fonts' section, select 'Subset embedded fonts' and 'Unembed fonts' if not needed. Remove unnecessary objects and user data under 'Discard Objects' and 'Discard User Data'.

What is 'downsampling' in PDF optimization and why does it matter?

Downsampling means reducing the number of pixels in an image within your PDF. It matters because fewer pixels mean a smaller file size, which helps the PDF load faster. You can control how much quality you lose by choosing the right 'dots per inch' (dpi) setting.

If my PDF is a scanned document, how should I optimize it?

If your PDF is a scanned document, you should use the 'Optimize Scanned Pages' option in Acrobat. This tool is designed to work specifically with scanned content, which often has different characteristics than digitally created PDFs. It can help clean up and compress scanned images more effectively, making the file smaller and clearer.

What is the difference between RGB and CMYK colors when optimizing a PDF for screen viewing?

Color Model Best Use File Size Impact. RGB (Red, Green, Blue) For on-screen viewing (websites, emails) Generally smaller file size CMYK (Cyan, Magenta, Yellow, Black) For professional printing Generally larger file size

Why should I unembed fonts when optimizing a PDF?

You should unembed fonts to make your PDF file smaller. When fonts are embedded, the font data is stored inside the PDF. If the viewer already has those fonts on their computer, unembedding them removes this extra data, reducing the file size. However, be careful, as unembedding can sometimes change how the document looks if the viewer doesn't have the correct fonts.

Optimize PDF for long-term archiving in Adobe Acrobat — How-to & AI prompts

AI prompts

3 ways to ask · copy any one

AExecute — “help me do it”Help me convert my PDF to a long-term archive format using...…+

Help me convert my PDF to a long-term archive format using Adobe Acrobat for [describe your document or purpose].

when the reply comes backWould you like tips for checking if your PDF is archive-ready?

BImprove — “do it better”Review my PDF and suggest ways to improve its long-term...…+

Review my PDF and suggest ways to improve its long-term archiving quality in Adobe Acrobat for [describe your situation].

when the reply comes backNeed help finding your PDF after saving it for archiving?

CDecide — “help me choose”Should I use PDF/A or another format for saving my...…+

Should I use PDF/A or another format for saving my [type of document] in Adobe Acrobat for long-term archiving? Explain why.

when the reply comes backWant advice on naming archived files for easy searching?

How to do it

the tool · the steps · what to avoid

1
Open the PDF file you want to optimize in Adobe Acrobat.
2
Go to the File menu and select Save As Other.
3
From the submenu, choose Archivable PDF (PDF/A).
4
In the dialog that appears, select the desired PDF/A standard (such as PDF/A-1b, PDF/A-2b, or PDF/A-3b) based on your archival requirements.
CautionSelecting a stricter PDF/A standard may restrict certain features, such as embedded multimedia or encryption.
5
Click Save and choose the location to save your PDF/A-compliant file.
6
Review the new file for any compliance warnings or errors reported by Acrobat, and address them if necessary.
Best practiceIf your PDF contains non-embedded fonts or transparency, use Acrobat’s Preflight tool to identify and fix issues before saving as PDF/A.

In the appWith the API

After saving, use Acrobat's Preflight panel to verify that your PDF meets the required PDF/A compliance level.

This runs in the Acrobat app - there is no separate API for this task.

Glossary

words on this page

PDF/AA special kind of PDF made for keeping files safe and unchanged for a long time.ExampleLibraries often convert old documents to PDF/A to ensure they can be read for decades.

ArchiveTo archive means to save something in a safe, final way so you can keep it for a long time.ExampleAfter finishing the project, we archive all related documents for future reference.

OptimizeTo make something work better for a specific use.ExampleYou optimize your website images to load faster for visitors with slower internet connections.

The real tasks

the one, listed here

Replace a large hero image with a compressed version so the page loads faster for users on slow connections.

FAQ

about this task

To optimize a PDF for long-term archiving in Adobe Acrobat, you usually save it as a PDF/A file. This format is designed to keep your document readable and unchanged for many years, making it safe for important records.

A regular PDF can change over time or may not open the same way on every computer. A PDF/A file is made to look the same everywhere and to last a long time, which is important for archiving.

Optimizing documents for archiving helps make sure they stay safe, readable, and unchanged for many years, which is important for legal, school, or business records.

Most PDFs can be converted to PDF/A in Adobe Acrobat, but some files with special fonts, videos, or forms might not work perfectly. Acrobat will usually warn you if there is a problem.

You should use PDF/A when you need to keep a document safe and unchanged for a long time, like for contracts, school records, or reports that may be needed in the future.

Optimize PDF for long-term archiving

When to use it

AI prompts

How to do it

Glossary

The real tasks

Who does this

FAQ

Sources

Adobe help

Other guides

When it fails