How do I reduce the file size of a PDF without losing quality?

Open your PDF in Acrobat. Go to File > Save as Other > Optimized PDF. In the Image Settings, choose to downsample images. For good quality, aim for 150 dpi for color/grayscale and 300 dpi for monochrome. Set JPEG quality to Medium/High (around 85%) as this often looks good without being too large. Review your PDF to check the quality after saving.

What is a good target resolution (DPI) for images when optimizing a PDF?

For color and grayscale images, a target of around 150 dpi (dots per inch) is often a good balance for screen viewing and general use. For monochrome (black and white) images, a higher target of 300 dpi is recommended to maintain sharpness. If image quality is very important and file size is less of a concern, you can choose 'Do Not Downsample' to keep the original resolution.

Reduce Cross-Project Clarifications in Adobe Acrobat — How-to & AI prompts

AI prompts

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DBecome — “help me grow”Creating a single construction set from multiple [consultants] eats two days per project…+

Creating a single construction set from multiple [consultants] eats two days per project because revisions aren’t aligned. Identify the patterns that cause the most rework when I merge consultant PDFs, and suggest one process change to enforce synchronized revisions and metadata so I need only one pass to assemble a clean construction set moving forward.

when the reply comes backPush once: ask it to sharpen the weakest part, and to say what it assumed.

How to do it

the tool · the steps · what to avoid

1
Open your PDF file in Adobe Acrobat.
2
Select the File menu, then choose Save as Other and then Optimized PDF.
3
In the PDF Optimizer dialog, review the default settings under each panel (such as Images, Fonts, Discard Objects, Discard User Data, and Clean Up).
4
Adjust any settings as needed, or leave them at their defaults for a basic optimization.
5
Click OK to apply the optimization and choose a location to save the optimized PDF.

In the appWith the API

You can preview the estimated file size reduction before saving by clicking the 'Audit space usage' button in the optimizer dialog.

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

Glossary

words on this page

DownsampleTo make an image smaller by removing some of its detail, which reduces the file size.ExampleTo make a large photo fit an email, you might downsample it to reduce its file size.

Unembed fontsTo remove the font information from a PDF, making the file smaller but requiring the font to be on the viewer's computer.ExampleYou unembed fonts from a PDF to reduce its file size before emailing it to a colleague.

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

Who does this

3 roles

Graphic DesignerAdministrative AssistantMarketing Coordinator

FAQ

about this task

Open your PDF in Acrobat.
Go to File > Save as Other > Optimized PDF.
In the Image Settings, choose to downsample images. For good quality, aim for 150 dpi for color/grayscale and 300 dpi for monochrome.
Set JPEG quality to Medium/High (around 85%) as this often looks good without being too large.
Review your PDF to check the quality after saving.

Unembedding fonts helps reduce the PDF's file size. When fonts are embedded, the font data is stored inside the PDF. If you unembed them, this data is removed. This can make the file smaller, but the PDF viewer needs to have the same fonts installed to show the text correctly.

For scanned PDFs, use the 'Optimize Scanned Pages' option in Acrobat. This tool is specifically designed to work with scanned images. It helps improve the quality of scanned text and images while also reducing the file size. After optimizing, check the document to ensure readability.

You should choose RGB color for PDFs meant for on-screen viewing because computer screens and most digital devices display colors using the RGB model. CMYK is for printing. Using RGB ensures that the colors in your PDF look accurate and vibrant when viewed digitally, and it often results in smaller file sizes.

For color and grayscale images, a target of around 150 dpi (dots per inch) is often a good balance for screen viewing and general use.
For monochrome (black and white) images, a higher target of 300 dpi is recommended to maintain sharpness.
If image quality is very important and file size is less of a concern, you can choose 'Do Not Downsample' to keep the original resolution.

Reduce Cross-Project Clarifications

When to use it

AI prompts

How to do it

Glossary

The real tasks

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FAQ

Sources

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When it fails