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In the process of printing my dissertation, I encountered problems where the text and figures were dithered and in gray instead of black. This exact problem has been discussed in an earlier question, and the problem finally got solved by a technician at the printing company turning the PDF into Postscript and then darkening the pages by two steps.

When discussing this problem, another employee there said that they often have this issue with LaTeX-generated documents, even having had Xerox technicians there to look at it, and said that they had claimed that LaTeX was never meant for print.

I find that very hard to believe since Knuth designed TeX to allow math to be better typeset. However, there does often seem to be problems with printing. Or is that perhaps always an issue, no matter how the document is generated?

gablin
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    TeX was never meant to print? What a silly statement. – egreg Mar 01 '18 at 15:42
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    I remember having printed my PhD thesis (generated with LaTeX and dvips) on Xerox printers -- they had problems with the PostScript (no particular or weird settings, however). On other printers, there were no issues ... so much for Xerox ;-) Every PDF I generated with LaTeX during the last years printed on every printer model I have access to without any problems, so TeX etc. is meant for printing .. –  Mar 01 '18 at 15:44
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    From the TeXbook: "dvi stands for 'device independent,' since texput.dvi is capable of being printed on almost any kind of typographic output device." Doesn't sound like something not meant to be printed... – Skillmon Mar 01 '18 at 15:50
  • @Skillmon unfortunately, like many terms, "device independent' really means "we tried it on a few devices and it seemed to work, so there you go" – Carl Witthoft Mar 01 '18 at 20:34
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    @CarlWitthoft Not in this case. In the case of TeX and DVI files, the “device-independent” meant something like: instead of outputting device-specific instructions for a specific printer, we'll output typesetting instructions in an abstract format, and you can write a “DVI driver” specific to your printer that interprets these typesetting instructions. (Analogous terms used in programming today are “bytecode” and “IR”.) (Of course, today most printers natively handle formats like PS or PDF, so we just need DVI→PS or DVI→PDF.) – ShreevatsaR Mar 01 '18 at 20:47
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    I wonder what percentage of (printed) STEM papers and books are composed in LaTeX? For a random sample, I have one called "Using OpenMP" on my desk at the moment. Right there on the copyright page: "This book was set in LaTeX by the authors and printed and bound in the United States of America". – jamesqf Mar 01 '18 at 23:08

1 Answers1

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This may or may not apply to your specific situation, but it is generally worth knowing:

(1) If the PDF has a color profile (*.icc) embedded, then many printers will produce CMYK "rich black" instead of pure K black. That is very undesirable for text, as it is intended for images. It will resemble rasterization.

Most TeX-produced PDFs will not have an *.icc embedded. But it is possible, especially if you are using PDF/X, and do not do it in a particular manner.

Do you have access to a program such as Adobe Acrobat Pro? Not the free version. If so, open one of your problem PDF files in it, and see if there is an Output Intent with embedded color profile. If that is the case, strip out the profile, and like magic your print will improve.

(2) If a page has both raster image and vector (text) objects, then any vector object that overlies any part of a raster image may be rasterized. In some cases, merely approaching the image will cause rasterization. Of course, everything is rasterized during print; but I refer to a lower-resolution rasterization that precedes final print rasterization.

This applies even if the underlying image is white or transparent there. In particular, it may apply if you are using a background or raster watermark.

(3) The above situations are not specific to TeX. If your printer has seen problems more frequently with TeX files, I surmise that the reason has to do with the content of the files, rather than the program used.

Also, some TeX users may still (in this day and age!) be using bitmap fonts here and there. The presence of a bitmap (raster) character may spread rasterization around to nearby vector text, like an epidemic.

(4) The information I provided above does not come from my own deep knowledge of the technology. Instead, I have noticed rasterization issues raised in other forums, by book writers (non-technical). They never heard of TeX. My information is a summary of responses from those who know.

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    "some TeX users may still (in this day and age!) be using bitmap fonts" it doesn't help that \usepackage[T1]{fontenc} automatically switches Computer Modern to raster without warning. – marczellm Mar 01 '18 at 21:02
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    @marczellm Not really; it uses whatever T1-encoded font is available on the system—and at least in TeX Live full, those are the vector fonts. (I've heard that otherwise you may need to install the cm-super package so that the vector T1 fonts get picked up, but I've never had to do that myself.) – ShreevatsaR Mar 01 '18 at 21:09
  • @marczellm Indeed, use of that line is often recommended precisely to ensure that postscript type1 fonts are used rather than metafont. The default built in to TeX is bitmap fonts with OT1 encoding, whereas many TeX distributions provide CM in the T1 encoding only in postscript format. Generally these days, you may well get type1 anyhow. But certainly switching to T1 was an easy way to ensure postscript in older distributions. – cfr Mar 02 '18 at 01:39
  • @cfr I think the user was talking about the opposite problem: changing from the older encoding OT1 to the (relatively) newer encoding T1 can result in a change from vector fonts to raster fonts. (This is typically a sign of a poor distribution or install, but seems to come up frequently, e.g. see Font is lower quality with T1 than OT1 on TeXLive or Why are Bitmap-Fonts used automatically? or its duplicates.) – ShreevatsaR Mar 02 '18 at 01:55
  • @ShreevatsaR I know. My point was that it certainly can go the other way. Including this line was one suggested way to fix the problem of poor quality rendering on screen precisely because it forced a switch from MetaFont to postscript. These days, most distributions default to type1 in OT1, but that was not the case in older TeX distributions. But these often provided T1-encoded CM as type1. Hence the advice. – cfr Mar 02 '18 at 02:06
  • "like an epidemic" hehe – Lightness Races in Orbit Mar 02 '18 at 02:18
  • Seems like I've raised an issue. :) –  Mar 02 '18 at 02:20
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    Some of us actually think the type 1 versions (and latin modern) are too thin and prefer the result one can get by changing parameters in the MetaFont. On our rather good printers at university, the result using MetaFont looks really good. This might be off topic here, sorry in that case. – mickep Mar 02 '18 at 08:14
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    @mickep Actually, on topic! I almost edited my reply, to mention this: The CM and LM fonts are beneath "book weight." That is, they are a bit too light for what is normally seen in a printed book, particularly the kind with long passages of text. This is why my own document class attempts to force Libertinus fonts as default, and actually issues a warning if (due to fonts not installed) the document reverts to LM. But then, my document class is for long passages of text, not math. –  Mar 02 '18 at 15:40