Comment by jws | Hacker News Reader

Comment by jws | Hacker News Reader

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The PDF specification, hosted by Adobe, free for you to download… (pay attention, this is a big PDF) https://opensource.adobe.com/dc-acrobat-sdk-docs/standards/p... Adobe specifically negotiated to make this freely available.

From the document:

This document you are now reading is a copy of the ISO 32000-1 standard. By agreement with ISO, Adobe Systems is allowed to offer this version of the ISO standard as a free PDF file on it's web site. It is not an official ISO document but the technical content is identical including the section numbering and page numbering.

I include that, so you can Google up a copy when the URL changes again. (Copy is disabled, I had to retype it. The misuse of "it's" is present in the original.)

As afar as I know, they have always posted the PDF format for free. ISO’s business model is different, they pay the bills by selling the documents.

For generating PDF, assuming you aren’t some sort of sociopath that wants to embed JavaScript or some custom plugin, then you can just drop back to 1.3 or so and deal with a simpler spec. Use the parts you need, ignore the rest.

Some time around 2000 I wrote a PDF generator to do my type setting, so that was 1.2 or 1.3. Very straightforward format.

> Very straightforward format.

The spec is 756 pages. For the 2008 spec. How is that very straightforward? My god.

Even the 2003 version clocks in at 696 pages and apparently includes "Interactive Forms", "Movies" and "Sounds".

Here's the link https://web.archive.org/web/20101214132912/http://partners.a...

How is that _straightforward_?

If you are generating documents you ignore all the stuff you don’t need. You are left with a sane dictionary based format with some optional compression. Ignore the compression until you feel the need to optimize. There is a bit of a complicated bit for random access where you need to remember and regurgitate the offset of various dictionaries. Beyond that it is just a bunch of drawing commands. Of course these are 20 year old memories and maybe the horror of part of it has burnt that from my memory.

I do agree that writing a reader would be brutal.

Thank you. I'll take a look at the older specs. I assumed that the 2.0 version would be the one with the best print quality and I should target that.

No, in general there is no difference in print quality between any PDF versions. I can think of only two exceptions:

· If you're embedding ICC color profiles, you need to be using at least PDF version 1.3, which came out in 01999.

· If you're embedding lossily-compressed raster graphics like JPEGs, while you can always improve the print quality further by switching to losslessly-compressed graphics like PNGs, you may be able to get better quality at a given filesize by using better lossy compression algorithms like JPEG-2000 or (for bilevel images) JBIG2. JPEG-2000 support was added in PDF 1.5 and is excluded from, I think, PDF/A. JBIG2 support was added in PDF 1.4, and also includes a lossless format.

I don't know of any features in 2.0 that would improve print quality over 1.5 in any way.

It’s probably worth spending a few minutes looking into PDF/A, which is a subset of PDF designed for archival. While it might not be a perfect fit for your needs (though it almost certainly is), being ISO standardised it might be a good source of documentation.

https://en.m.wikipedia.org/wiki/PDF/A

Note, however, that this is not the current version of the standard. The current standard requires paying money to ISO (who are the big baddies in this story and not Adobe—they have all their standards locked behind a paywall). That said, this version is probably adequate for most needs.

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