Common PDF Compression Problems and How to Fix Them—Detailed Guide

blog 11

We all know that PDF compression has its benefits. For instance, compressing a PDF reduces file size, which makes it easier to store and share. It speeds up transfers and saves storage space on devices. Many compression tools maintain quality while shrinking the file, which improves overall efficiency.

However, compressing a PDF is not always as easy as it looks, especially when you are compressing large files. Apart from that, you may also face other PDF compression issues.

In the text to follow, you will learn about some common PDF compression problems and how to fix them.

  1. The PDF File Becomes Corrupted

    2. PDF files can become corrupted after compression for several reasons. For example,

    • The file might not have downloaded correctly
    • The compression was too extreme,
    • The hard drive might be full, or
    • There could be an issue during file transfer between devices.

    If the problem happened during the download, try downloading the file again to see if that helps.

    If the problem persists, here are some general remedies to try.

    • Restore the previous version by locating the PDF in your saved files. Right-click on it and select "Restore previous versions."
    • Check the font. Missing or incompatible fonts can cause strange text.
    • Make sure your software is up to date. Update the program that created the PDF or update Acrobat Reader.
    • Clear the cache. Sometimes, clearing the cache in your PDF viewer can fix the problem.

    If the problem still persists, you can fix a corrupted PDF using Adobe Acrobat Reader. Here is how:

    • The problem could be that your Adobe Acrobat Reader is outdated. Open the app, go to Help, and click "Check for updates." If there are updates available, install them. Then, try opening your PDF again.
    • Some files needed by Adobe may be damaged. You can fix this by going to Help and click "Repair installation." If the issue still happens, uninstall Acrobat and install the latest version.
    • If the PDF worked before it was corrupted, you might be able to restore an older version. Find the PDF on your computer, right-click it, and choose "Restore previous versions." You can then select and open an earlier, uncorrupted version.
    • If you don't have an older version, try converting the PDF to another file type, like PDF to Word document. This may not fix the PDF directly, but it will help recover any important information.

  2. Fonts are Missing or Appear Incorrectly

    3. Missing fonts is another common issue users might face after compression. If a compressed PDF is missing fonts, you can either embed the fonts or add them from another source

    Here are some possible solutions to address this problem.

    Embed fonts

    • Open the PDF in a program that allows font embedding.
    • Select the fonts you want to embed.
    • Choose the option to embed the fonts.
    • Save the file.

    Add fonts from another source

    • Find the missing fonts.
    • Copy the font file to a location your programs can access.
    • Restart the program you are using.

    For Microsoft Word

    • Update the document options.
    • Check the "Embed fonts in this file" box.
    • Save the file.

    For Adobe Acrobat

    • Visit the Adobe Fonts website.
    • Search for the missing fonts.
    • Add the fonts using Creative Cloud desktop.

  3. Loss of Image Quality

    4. One common issue with PDF compression is the loss of image quality. When a PDF is compressed, images often lose resolution, which causes them to appear blurry or pixelated. This can be a problem when the PDF contains high-resolution images, such as product photos or technical illustrations.

    The loss of clarity can make the document look unprofessional or harder to read, especially when images are key to the content.

    Here are some potential solutions:

    Adjust Compression Settings

    Begin by adjusting the compression settings in your tool. Choose moderate settings instead of high compression levels, as the latter may reduce image quality too much. Some tools also allow you to control the amount of compression for individual images, keeping important ones sharp.

    Resample Images

    adjust the resolution of images to suit the document's needs before compression. For instance, print-quality images should be at 300 DPI, while screen images can be reduced to 150-200 DPI. This helps reduce file size while keeping image quality intact.

    Use Image Editing Tools

    Resize and optimize images with tools like Photoshop or GIMP before embedding them in the PDF. This ensures the images are appropriately sized and clear, reducing the final file size.

    Consider Image Format

    The image format also affects quality. JPEGs are good for smaller file sizes but can lose quality, while PNG or TIFF formats preserve quality better. Choose the right format depending on the document’s needs.

  4. Compression Takes Too Long

    5. Compressing large PDFs, especially those with many images, complex graphics, or multimedia, can be very slow.

    The process requires significant computing power, and depending on the document’s size, it may take a frustratingly long time.

    This delay can be worse if the compression tool is inefficient or if the file contains high-resolution images or large embedded files.

    Here are some potential solutions.

    Split Large PDFs

    If you have a large PDF, consider splitting it into smaller sections. Compress each part individually to speed up the process. Once compressed, you can merge them back into one document.

    Use Cloud-Based Services

    Cloud-based PDF compression tools like compresspdfonline often handle large files faster than local tools. These platforms use powerful remote servers to compress files quickly.

    Reduce Image Resolution

    Reducing the resolution of images in the PDF can speed up compression. For example, lowering image resolution from 300 DPI to 150 DPI makes it easier for the tool to process them.

    Remove Unnecessary Components

    Delete unnecessary elements like annotations, metadata, or hidden layers to make compression faster. Reducing blank spaces and optimizing fonts can also speed up the process.

  5. Loss of Interactive Elements

    6. One common problem with PDF compression is the loss of interactive elements, like form fields, hyperlinks, and JavaScript. These features are crucial for functionality, especially in fillable forms or documents with embedded links. However, some compression tools prioritize reducing file size and may strip out these interactive features.

    Here are some possible solutions to address this problem.

    Check Compression Settings

    Review the settings of your compression tool before compressing. Many tools let you choose what to keep or remove. Make sure settings do not delete form fields, links, or JavaScript.

    Use Tools that Support Interactivity

    Choose a tool that can preserve interactive features. Basic or free tools may not handle this well, but advanced tools can better maintain these elements during compression.

    Use PDF/A Format

    If you need to preserve a PDF for long-term storage, use the PDF/A format. This version of PDF ensures all interactive elements are kept intact, making it ideal for documents with forms or links that need to stay functional for years.

    Test the Document After Compression

    Check the document carefully after compression. Ensure that form fields are still fillable, links are clickable, and JavaScript functions work properly. This is especially important for documents used in legal, business, or educational settings.

  6. File size not reduced even after compression

    7. There is a possibility that the compression tool does not compress the PDF file as expected. If the size of a PDF file doesn't change after compression, there could be several reasons for this.

    • The file is already compressed: If the PDF is already compressed, it may be hard to reduce the size further.
    • Compression software is not effective: Some compression tools might not work well with certain files.
    • The file is encrypted: If the file is encrypted, it may not compress easily.

    Here are some potential solutions.

    Use Advanced Compression Tools

    Free tools may not work well for large or complex PDFs. Paid tools give you more control in such cases. You can adjust image quality, fonts, and other elements to find the right balance between size and quality.

    Remove Unnecessary Elements

    PDFs often contain extra elements that make the file size larger. These include metadata (author, date), redundant objects (duplicate images or fonts), and unused items (hidden form fields or annotations). Removing these can help reduce the file size.

    Optimize PDF Content

    Optimizing content is another way to shrink PDF size. Flatten vector graphics (like charts or drawings) to make them easier to compress. Reduce image quality for non-essential visuals while keeping important ones clear.

    If the PDF has multimedia like videos or audio, remove or compress them to save space. Finally, consolidate fonts by embedding only the necessary ones to reduce the file size further.

  7. File is already compressed" Error Message

    8. Sometimes, the users may have trouble compressing a PDF in Adobe Acrobat. For example, whenever they try to compress, an error message says, "File is already compressed," even though the file is not compressed. This error happens with multiple PDF files.

    Here are some possible solutions:

    • Try Another PDF: Test compressing a different PDF file to see if the issue is with just one file.
    • Update Acrobat: Make sure Adobe Acrobat DC is up to date. Go to Help > Check for updates and restart your computer after updating.
    • Repair Acrobat: If you are using Windows, go to the Help menu and choose "Repair installation" to fix any problems with the software.
    • Check Compression Settings: Some files might have hidden compression. Try saving the file as PDF/X-4 (File > Save as other > PDF/X > Settings) and then try compressing it again.
    • Use the Optimizer Tool: If you are using the optimizer tool, adjust the settings to make the file compatible with Acrobat 8.0 or later. You can also try the "Preflight" or "Fixup" options in the Print Production tools for more help.

    So, this was our guide on common PDF compression problems and how to fix them. Let us know if you find any other issues so that we can look up for possible solutions.