Organising pages
Does combining PDF pages break links, forms or text?
Text stays selectable and vectors stay sharp because pages are embedded as content, but links and form fields are annotations rather than content and are lost, so pages carrying them should be left alone rather than combined.
PDF tools use the word "lossless" loosely. Here is what survives when pages are combined onto one sheet, and what doesn't.
What survives
Text stays text. Pages are placed as *page content*: the same drawing instructions, moved onto a new sheet. The glyphs are the original glyphs, so the result is still selectable, still searchable, and still copies out cleanly. Nothing is rasterised.
Vector graphics stay vector. Charts, diagrams and logos drawn as vectors remain vectors, so they stay sharp at any zoom.
Images keep their resolution. They are placed, not re-encoded. If a page is drawn at full size, its images are exactly the images they were.
Fonts come along. The embedded font programs the pages reference are carried into the new document.
What does not survive
Links. A clickable link in a PDF is not part of the page content. It is an *annotation*, a separate item that holds a clickable area and where it goes. Placing a page as content brings the drawn text, including the blue underline of a link, and leaves the annotation behind. The link looks like a link and does nothing.
Form fields. Same reason. A text box, a checkbox, a signature field: all annotations, all attached to the page rather than drawn on it. Combine the page and you get a picture of the form that you can't fill in.
Comments and highlights. Also annotations. Also lost.
Page-level structure. Bookmarks pointing at a page that no longer exists on its own, and tagged-PDF reading order, do not come through intact. If the document has to remain accessible to a screen reader, this matters more than everything else on this list.
What a careful tool does about it
A warning isn't enough. The tool should check before it combines anything.
SmartShrink checks every page for links and form fields and excludes those pages from combining entirely. They stay as they are. You get fewer pages where fewer pages are safe, and the pages that carry interactive content are untouched.
On documents full of links to other pages, you get a smaller reduction. That is worth it. A ninety-page contract that becomes fifty pages with dead signature fields is not a better document.
How to check your own result
After combining, open the output and:
- Select some text and copy it. If it pastes as text, the content survived.
- Click a link you know was there. If it is dead, that page should not have been combined.
- Tab through a form. If focus does not move between fields, the fields are gone.
- Zoom to 400% on a chart. Sharp means vector; blocky means something rasterised it.
If test 1 fails, the tool has turned your text into a picture of text. That is a real loss, whatever the file size says, so don't use that result.
The order to do things in
If a document needs both editing and shortening, edit first. Combining pages makes the layout harder to work with afterwards, and anything you add in the editor after combining is added to the new sheet rather than to the original page.
Common questions
Why can links not be preserved?
Because a link is an annotation attached to a page, not part of what the page draws. Embedding a page's content onto a new sheet carries the drawing and not the annotations attached to the old page.
Will my scanned document still be searchable afterwards?
Only if it was searchable before. Combining does not remove a text layer, but it doesn't add one either. A scan with no OCR is still a picture of words. Run OCR PDF first if you need the text.
Is the text turned into an image?
No. Pages are placed as content, so text stays text. If your output has text you can't select, something turned it into an image, and you should find out what.