When to flatten a PDF's form fields and comments

Flattening sounds technical, but the idea is simple. A form field or a comment in a PDF is a live object sitting on top of the page. It can be changed, moved, hidden or deleted. Flatten draws those objects into the page itself and removes them as live objects, so what you see becomes part of the page like any other printed text.

PDF by Zaweba can flatten form fields or comments. There is also Flatten fill and sign, which does the same thing for Fill and sign items only. Each one is a small decision with lasting effects, so it is worth thinking about when to use them.

Why you might want to flatten

The main reason is to fix things in place. A filled form you send to someone can still be changed by them if its fields are live. Flattening a copy turns the answers into page content, so the copy shows exactly what you filled in and nothing more.

Another reason is consistency. Different PDF readers can show live form fields and comments a little differently, and some may hide comments altogether. Once flattened, they look the same everywhere because they are simply part of the page.

Flattening also tidies a document for a final version. A report reviewed with many comments may be clearer, once agreed, with the marks drawn in, or you may decide to delete the comments instead.

Why you might not

Flattening removes the live objects, and that is the point, but it is also the cost. A flattened form can no longer be filled, reset, cleared or have its data exported, because there are no fields left. Flattened comments can no longer be replied to, edited or listed as comments.

So never flatten your only copy. Keep the live version and flatten a copy for sending or archiving. That way you can still change the form later, export its data, or pick up the review where it left off.

Flatten fill and sign

Fill and sign items are the quick text, ticks and signature images you place on a page that has no proper form fields. Flatten fill and sign works on just those items, drawing them into the page while leaving other things alone. That is useful when a document has comments from a review that you want to keep as comments, but your own filled details should be fixed in place before you send it.

Flattening and the other safety tools

It is important to know what flattening does not do. Drawing something into the page does not hide what was there before. If you place a box over some text and flatten it, the text underneath may still be in the file. For removing sensitive information properly, redaction is the right tool, because when redactions are applied the text and picture pixels under the marks are removed from the file. The check for unsafe redactions looks for exactly this kind of cover-up that doesn't really hide anything.

Flattening is not the same as protection either. If you want to stop people changing a document, password protection with permissions is the tool for it, and a digital signature shows whether anything changed after signing. Flattening simply makes fields and comments part of the page.

A sensible routine

Finish filling or reviewing. Save the live file under its working name. Save a copy under a final name and flatten that copy, using Flatten for forms or comments, or Flatten fill and sign for your quick-fill items. Look through the flattened copy to make sure everything appears as expected, then send it.

Treated that way, flattening in PDF by Zaweba becomes a reliable last step rather than something you regret, and like every other tool in the app it runs offline on your PC.