Talk:PDF

True icon
Which of these icons is more reliable: or ? — Preceding unsigned comment added by Hooman Mallahzadeh (talk • contribs) 13:14, April 19, 2022 (UTC)

File Format: PDF as the size of a country
The section currently states "Page dimensions are not limited by the format itself. However, Adobe Acrobat imposes a limit of 15 million in by 15 million in, or 225 trillion in2 (145,161 km2)" and then cites the PDF specs sheet for version 1.7. However, this seems like a calculated number that is not explicitly stated in the adobe specsheet being stated. It does say (page 350) that there is a max size of 200 x 200 inches. Can someone provide a brief explanation of how this number is arrived at on the article page?

It appears that is has something to do with the fact that each unit is of 1/72 (inches) and there should be a maximum "14,400 by 14,4000 units", but I don't understand how this works out to 15 million. Could someone make the article more transparent about this calculation since it is not explicitly stated in the document being cited? Textaural (talk) 07:27, 1 July 2023 (UTC)


 * Page 1,128:
 * "Beginning with PDF 1.6, the size of the default user space unit may be set with the UserUnit entry of the page dictionary. Acrobat 7.0 supports a maximum UserUnit value of 75,000, which gives a maximum page dimension of 15,000,000 inches (14,400 * 75,000 * 1 ⁄ 72). The minimum UserUnit value is 1.0 (the default)." Sockwell162 (talk) 07:34, 1 July 2023 (UTC)
 * The manual it references is from 2006 and Acrobat is now on version 22. I wonder if there's a newer version. Sockwell162 (talk) 07:38, 1 July 2023 (UTC)

I fixed the misrepresentation of the relationship between PS and PDF.
The previous author seems to not have understood the word „tokenized”, and not read the PostScript language reference. Being a programming language, of course PS is tokenized and parsed by the interpreter too, before/during interpretation. PDF is simply “unrolled” PS so that it is purely declarative, and packaged with its dependencies. Professor Brailsford of Nottingham university explained this quite well in some Computerphile videos. And he knows/knew the people who developed PDF personally.

I improved the whole section. I also made it a bit more neutral; as it seems much knowledge about PS (especially about the extend of its use case, compared to PDF being just about documents) is almost lost nowadays, leading to a natural underestimation and bias from people who don’t know they don’t know enough to make that decision. I know because I thought like that too until I looked into it. (The language reference is quite nice to read.) E.g. the fact that PS is based on Forth and Lisp (and frankly nicer than both). Or that SVG is basically the XML version of the PS in PDF. … All information that is almost lost, and would quickly get deleted by such people who don’t know they don’t know … for not being up to the standard … of confirming their beliefs that are based on sources that already lacked those forgotten details about the big picture and ideas back then. — 109.42.178.164 (talk) 00:19, 28 December 2023 (UTC)

NDA 76 regular course results
ND 102.67.23.148 (talk) 13:00, 10 June 2024 (UTC)