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Once my college professor was working on her research paper and told me she was struggling get text to stay underlined. Assuming a simple user error, I expected to help her out in 5 minutes.

Over three hours later, we discovered that the combo of her specific video card driver version along with her specific printer driver version would keep text from printing out underlined.



Much better than the Xerox bug that caused numbers in scanned documents to get changed.

https://www.zdnet.com/article/xerox-scanners-alter-numbers-i...

Ouch


I kind of remember this one. It wasn't really a bug. I think Xerox used software that was known to not be 100% trustworthy to recognize numbers when used at a certain compression level. It was even in the manual if i'm not mistaken.


The manual pointed out this can happen at higher compression levels, but they were able to reproduce it at all levels.


How does one discover something that niche in ~3 hours?


Lots of internet searching and even a few calls to HP support. To be honest, we dismissed some of the earlier suggestions to upgrade the other drivers from other vendors... so maybe most of the time was us getting past ourselves and our disbelief.


Huh? How does a video card affect printing?


One of the ways to print things (especially on windows) is Via GDI. [0]

Basically using the OS's rendering to make a raster that is then sent to the printer. The main thing the printer's driver does in this case is know how to take the bitmap and tell the printer to print the bitmap (i.e. chunking data and/or sliding the right commands into the bitmap stream)

Contrast to, say, PostScript which allow for more compact and better scaling definition of what to print. This obviously works better for quality, however for a long time the issue was you then had to have sufficient processing power on the printer itself to handle it.

[0] - Search for 'GDI Printer' for a little more info.


Interesting! So that's why I used to get crappily rasterized printouts of PDFs in Chrome a few years ago.

I had thought printers could be trusted with their own rendering, but of course that is another can of worms...


More relevant to the bug is the fact that GDI can do its own rendering, or send commands to a driver, usually for GPU hardware acceleration, but the same applies to printers.


It often did, particularly on older versions of Windows. I helped uncover a bug in Epson printer drivers ~20 years ago that was caused by a specific graphics card.


20+ years ago I was in tech support and had to help someone figure out an issue where her document wouldn't print on a Brother printer. Turns out a section divider line would block the entire doc from printing (by crashing the app) if the line's end-cap style was set to square rather than rounded.


A lot of rendering will go through the video card if available, like the jvm does this as an optimization.


Ah interesting. That makes sense. I had no idea.




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