Flatten PDF

Frequently asked questions

• What does it mean to flatten a PDF?

  Flattening a PDF means converting all interactive and layered elements – including form fields, annotations, and digital signatures – into a single, static layer. This process makes the document uneditable and ensures that all content appears exactly as intended, regardless of the viewing software or device.
  
  With Lumin, you can achieve this by using our print-to-PDF feature, which effectively "locks in" all the visual elements permanently.

• Does flattening a PDF reduce quality?

  Flattening your PDF keeps everything looking exactly as it should. The process merges interactive elements — like form fields, annotations, and layers — into one clean document without messing with the visual quality.
  
  Your text stays crisp and images remain clear. While some ultra-high-resolution graphics might see minor adjustments during flattening, the quality that matters most is preserved.
  
  You'll end up with a consistent document that's secure and ready to share or print — without the complexity of layered structures.

• Will flattening remove form fields and annotations?

  Using our flattening process doesn't remove form fields and annotations, but it does convert them into permanent, non-interactive content.
  
  Filled form fields become regular text, checkboxes and radio buttons become static marks, and annotations become part of the document's visual layer. The content remains visible and intact, but users can no longer modify, clear, or interact with these elements.

• Should I flatten a PDF before printing?

  Flattening your PDF before printing is a smart move. It locks everything in place so what you see on screen is exactly what comes out of the printer.
  
  Without flattening, these elements can get messy or disappear entirely, especially when you're printing from different devices or printer setups. Flattening creates a clean, simplified version that prints consistently every time.
  
  Got fillable fields, signatures, or markups in your PDF? Flatten it first to avoid those annoying formatting surprises and missing content that can ruin an otherwise perfect document.

• Does flattening reduce PDF file size?

  Flattening a PDF doesn’t necessarily reduce its file size. The result depends on how the PDF was originally created and how complex its interactive elements (like form fields, annotations, or layers) are.
  
  In some cases, flattening can simplify the document and make it smaller. But in others (especially if flattening converts vector graphics or interactive elements into high-resolution images), the file size might actually increase.
  
  If you need to reduce the size of your PDF once flattened, try our PDF compression tool.

• Can I highlight or edit before flattening a PDF?

  Yes! One of the key advantages of using Lumin is the ability to make edits before flattening.
  
  Add highlights, insert text, create annotations, fill out forms, or make any other modifications using our comprehensive PDF editor. Once you're satisfied with all changes, use the print-to-PDF feature to flatten the PDF and lock everything in permanently.