I need to send a bundle of archived reports to the [recipient=audit team] and their mailbox limits mean large files wi…
Open the PDF you want to archive in Adobe Acrobat.
Select File > Save As Other > Archivable PDF (PDF/A).
CautionPDF/A conversion may remove features like audio, video, and JavaScript that are not permitted in archival PDFs.
In the PDF/A conversion dialog, choose the desired PDF/A standard (such as PDF/A-1b for basic long-term preservation).
Best practicePDF/A-1b is widely accepted for basic archival needs, but check your organization's requirements.
Click OK to convert and save the PDF as a PDF/A file.
Open the newly saved PDF/A file.
Select File > Save As Other > Reduced Size PDF.
In the Reduce File Size dialog, select the desired compatibility level (choose the lowest version that meets your needs for maximum compression).
Best practiceFor archival, using the lowest compatible version maximizes compression but may reduce compatibility with very old PDF viewers.
Click OK and save the reduced-size PDF/A file.
Best practiceBefore archiving, use File > Properties to remove unnecessary metadata and hidden data for further size reduction.
After converting to PDF/A, always review the document to ensure all essential content remains accessible and readable.
This runs in the Acrobat app - there is no separate API for this task.
Compressing a PDF mainly reduces the size of images by lowering their resolution (DPI) or removing some color information. This makes the image file smaller. Text, however, is stored differently in a PDF, often as vector graphics or fonts, which are already very small and do not lose quality when the file is compressed. So, text always stays sharp, but pictures might look less clear if compressed too much.
If the report will be printed, you should use 'Low (High Quality)' compression or avoid compressing it too much. Printing needs images to be at least 300 DPI for good quality. High compression often reduces images to 72-100 DPI, which looks poor in print. Always check the final PDF to ensure image quality is acceptable before sending.
Compressing an original PDF means you are reducing its size for the first time, starting with the best possible quality. This gives you the most control over the final output. However, compressing an already compressed PDF means you are degrading the quality even further from a file that has already lost some information. Each compression cycle reduces image quality more, so it's always best to work from the original file to avoid unnecessary degradation.
It's important to match the compression setting to its final use because different uses require different image qualities. For example, a PDF meant for email or viewing on a screen can have lower quality images to keep the file small. But a PDF meant for printing needs high-quality images (300 DPI) to look good. Choosing the wrong setting can make images look bad or make the file unnecessarily large.