Rotate PDF

Because what you changed was almost certainly a view setting rather than the document. Browser PDF viewers in particular give you a rotate button that turns the page for as long as the tab is open and writes nothing back — there is often no save step at all, so nothing warns you that it was temporary. Desktop editors are more likely to keep it, but only if you save afterwards, and in some of them save means save a copy. The test takes seconds: close the file, reopen it, and see which way up it starts. If it is sideways again, the file itself was never touched.

Not when it is done by changing the page's orientation, as it is here. No pixels are resampled and no text is re-encoded, so there is no generation loss to accumulate — a page can be turned and turned back with nothing lost along the way. What does cost quality is the workaround people fall back on when a rotation will not stick: printing to PDF, or exporting the pages as images, turning those, and rebuilding a document from them. That flattens live text into a picture of text, which cannot be searched or selected afterwards, and it is worth avoiding for anything anyone might need to quote from.

No, and no tool can write that into the page, because page rotation in PDF is defined only in multiples of 90 degrees. A sheet that came out of a feeder two or three degrees off is a skew problem, and skew lives in the pixels of the scan rather than in the page's orientation value. Fixing it means straightening the image: rescan with the paper squared against the guides, use the deskew or straighten option in your scanning software, or take the page into an image editor, rotate by the small angle and crop back to a rectangle. Expect the text to soften a little, since that rotation genuinely resamples.

Find their numbers first by scrolling the file in any viewer and noting which sheets sit the wrong way — nothing detects orientation for you. Then put them in the Pages box as single numbers, ranges, or a mix of both in the style 1,3-5. Spaces around the numbers are ignored, the order you type them in does not matter because the list is sorted before use, and naming the same page twice does no harm since it is still turned once. Leaving the box on 'all' or emptying it takes every page. Anything the box cannot parse stops the run with a message instead of quietly rotating the wrong sheets.

No. The file is read by the page you have open, rewritten by a PDF library running as JavaScript in that same tab, and handed back through a link the browser builds from data already on your machine. There is no upload step in the code and no server takes part in the rotation, which matters more here than for most jobs — the documents people need to turn are usually scans of something personal: a signed agreement, an identity page, a letter from a hospital. Rotating a second time throws the previous link away, and there is no history, no account and nothing to come back to later.

Encryption is the usual answer. A PDF can carry one password that controls opening it and a second that restricts what may be done with it, and a file carrying either is refused here rather than opened partially, since the loader is instructed not to ignore encryption. Remove the protection in the application that applied it, or open the file with its password in a full PDF editor and save an unprotected copy, then come back. The other cause is real damage — a download that stopped early, or a file written by a broken export. Those often still open in a forgiving viewer while failing a stricter parser outright.

A duplex scan flipped on the wrong edge. When the sheet is turned over on its long edge but the scanner expects a short-edge flip, or the reverse, every back side arrives 180 degrees against its front — which is why the fault lands on the even pages and never the odd ones. The lasting fix is the scanner setting, so for a long document it is worth feeding the stack through again. For one you already have, list the even pages and turn them 180 in a single pass. There is no odd or even keyword, so they have to be typed out: 2,4,6,8 and onwards.

It should not, because turning a page changes an orientation value and leaves the page contents where they were. Everything drawn on the sheet keeps its position relative to that sheet, so a search still finds the words and a text layer added by OCR turns along with the image it sits behind. Two things can still look odd. Selection can highlight in the old reading direction in some viewers, which is a display quirk rather than damage. And text that was drawn sideways onto an upright page stays sideways relative to the page after rotation, because the characters were placed at an angle in the content itself.