You changed one line in a PDF and now it is the only thing anyone will notice. Here are the common tell-tale signs, what causes each one, and how to fix it.
The new text is in a different font
Cause. The editor could not use the original font, so it fell back to its default. PDFs usually carry only the letters they used (a "subset"), and many editors will not draw from a subset or cannot find the face at all.
Fix. Use an editor that reuses the font stored in the file and, when a letter is missing, picks the nearest face by name and letter width rather than a generic default. That is how the PDF text editor works. More detail in how to change text in a PDF and keep the same font.
It is slightly too big, too small or too bold
Cause. The editor rounded the size to a whole point, or treated a weight it did not recognise as regular or bold.
Fix. Edit the existing text rather than adding a new text box, so the size and weight are copied from the line itself instead of being chosen from a menu.
It sits higher or lower than the rest of the line
Cause. A text box was placed by eye. Text boxes are positioned by their top edge, while the original text sits on a baseline, the invisible line the letters rest on. Two fonts at the same size can put their letters at different heights inside a box.
Fix. Replace the text in place so the new words go on the original baseline. Nudging a text box by hand rarely gets it exactly right.
There is a white rectangle around it
Cause. The old text was covered with a white box, and the page is not pure white. Scans, tinted paper, certificates and letterheads are cream, grey or patterned, so the box stands out.
Fix. Remove the old letters instead of covering them. On a normal PDF that means editing the text itself. On a scan it means rebuilding the paper behind the letters. The scanned PDF editor does that, and the white-out tool matches its box to the paper colour rather than using pure white.
The spacing between words is off
Cause. The original line was justified (stretched to fill the width, with wider gaps) and the new text uses normal spacing, or the new font's letters are wider or narrower than the old ones so the line ends in the wrong place.
Fix. Keep the original gaps and spread small width differences across them, so the line still ends where it did. PencoPDF does this for you on the line you edit.
The colour is not quite right
Cause. A lot of "black" text is really a very dark grey or navy, and scans pick up the colour of the ink and the paper. New text in pure black looks heavier.
Fix. Take the colour from the text being replaced. PencoPDF reuses the colour of the line on a normal PDF and measures the ink on a scan.
The old words still show through, or can be copied
Cause. They were never removed, only hidden. Select the area, or copy and paste the page into a text editor, and the old words come out.
Fix. Edit the text itself so the old letters are deleted from the file. If the content is confidential, read whiteout vs redaction before you send the document anywhere.
A quick check before you send it
- Zoom to 200% and compare the edited line with the one above it.
- Try to select and copy the line: you should get the new words and only the new words.
- Print one page, or view it on a phone. Differences that hide on a big monitor show up at a different size.