Photo by tomeppy
Have you ever wondered what makes up a PDF document? What the inner workings are like? OK probably not, but Tad over at Paper Jammed has, and he has put together a delightfully geeky rundown of some of the internal workings of the PDF document that allow for multiple changes.
(I bet you thought PDFs were read only, didn’t you?).
It was at that moment that I recalled a peculiar feature of the PDF file format: it is designed to support nondestructive updates, allowing people to make vast changes to a PDF document while still retaining the original document, fully intact. I did a few experiments and was surprised with the results.
His point: If you want to make sure that your stuff that you thought you removed WAS removed, use a redaction tool. Good advice.