back to article Xerox copier flaw changes numbers in scanned docs

A German PhD student has found a flaw in some Xerox Workcentres that fudges the numbers on some scans thanks to poor data compression. Last Wednesday, computer science student David Kriesel was scanning in some building plans on a Xerox WorkCentre, and when checking the copies he found some of the dimensions of the plans had …

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Anonymous Coward

Geez, let's hope aircraft designers use Kyocera brand copiers. Can you imagine design specs for an aircraft fuselage being morphed?

That is simply unacceptable. How many companies use Xerox for copying financials for audits, evidence in a criminal trial, pharmacies for medication instructions, etc. The mind boggles. I don't care if they say 'errors may occur'. This should not happen, period.

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Anonymous Coward

Aircraft designers

Um, photocopiers tend not to go up to A0.

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Anonymous Coward

Re: 'this is simply unacceptable'

If a reliable analogue (or simple digital) photocopier fouled up due to small typeface and poor resolution, it would be reasonably obvious on the copy.

This Xerox product seems more like a scanner, OCR, random editor, and printer.

"It really is up to the user to ensure that the settings meet their needs."

And to the vendors to tell people how their products are working, to the extent that they are actually unreliable on settings which may initially appear sensible.

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Re: 'this is simply unacceptable'

What is this Xerox device if not a printer combined with a high quality scanner?

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Thumb Up

Re: 'this is simply unacceptable'

If a reliable analogue (or simple digital) photocopier fouled up due to small typeface and poor resolution, it would be reasonably obvious on the copy.

This Xerox product seems more like a scanner, OCR, random editor, and printer.

THIS.

Anyone who doesn't get that point?

It's like the government giving you the "unvarnished truth". But then you look closer, underneath the retouched crisp type and....

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WTF?

Re: 'this is simply unacceptable'

@ribosome 'Personally I feel managements should get rid of copiers and replace them with printers and good quality scanners'

WTF dude?

It's not necessarily cheaper, there IS just as much to go wrong, it takes up twice the space and requires a computer in the middle just to do a photocopy

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Anonymous Coward

I've used these copiers...

to photocopy my 6" penis and it came out 8" long. RESULT.

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Re: Aircraft designers

Um, photocopiers tend not to go up to A0.

Your standard office ones don't. But large format ones do exist. Any department that does a reasonable amount of work with maps and plans will have a large format A0 copier to hand.

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FAIL

Re: 'this is simply unacceptable'

Wrong.

There is a very clear difference between "this low resolution copy is so crappy I can't tell the difference between this 6 and this 8" and "I can clearly see this is an 8 yet on the original it is clearly a 6"

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Anonymous Coward

@ Jolyon Smith - Re: 'this is simply unacceptable'

If it was 'clearly', it would not have been replaced. Apparently the copy quality was set so low and the original so bad that this combination led to the substitution. There's a warning in the manual, if anyone could ever bother to read it, about small fonts and compression. This would not have happened with larger fonts or a more sensible setting.

Strange that users think they don't need to read a manual and yet think that the default settings should be altered at whim.

I call this pebkac, but I've worked for Xerox for some years and seen how creatively destructive users can get: trying to put kiss-cut sticky-back labels through an ADF, or printing on stapled pages . . .

This is almost a non-story.

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Boffin

Re: Aircraft designers

> Your standard office ones don't. But large format ones do exist.

+1. I actually looked at a few from HP last year because some folks in my department demanded a large format printer. In the end we went with one that does not have a copier feature built in, which in hindsight is a big mistake when clients started sending us A0 blueprints and asking us to digitize those!

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WTF?

Re: 'this is simply unacceptable'

Yes, it is unacceptable. When text goes fuzzy, you know it’s unreliable. When it is substituted, then there is a real potential for disaster.

Publishing a disclaimer is also unacceptable. It’s simply an admission of guilt and does not of itself make the behavior OK. A photocopier which may or may not reproduce your documents correctly is just asking people to shop elsewhere.

Blaming the user is also unacceptable. Using a shared copier, you can’t expect all users to be aware of whatever settings may or may not have been applied by someone else. It might even have been the service technician.

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Holmes

Re: @ Jolyon Smith - 'this is simply unacceptable'

> I call this pebkac

It isn't. It is bad design.

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Anonymous Coward

Re: "I've worked for Xerox for some years"

"I've worked for Xerox for some years"

"Strange that users think they don't need to read a manual"

Strange that someone claiming to be an employee of a photocopier company wants to appear ignorant of the typical environment in which their products are used - dozens of users per shared "workgroup" device, generic printing capability outsourced, manuals never seen by end users, no online manual downloadable/browsable from the device for easy access (or if there is one, it doesn't tell users about it, and IT certainly don't).

"how creatively destructive users can get: trying to put kiss-cut sticky-back labels through an ADF"

You should see what happens when those labels go through the fuser (that's the hot high pressure bit, for readers who aren't aware). Or when OHP foils (remember them?) of the inkjet kind go through the fuser. I've seen that, because I'm out there on the same planet as the copier users. What planet are you on?

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rlc

Re: I've used these copiers...

Yes, but its low resolution...

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Re: 'this is simply unacceptable'

I am not an expert, but I believe that the combination of a small font face, 200 dpi equivalent and anything else on an analog copier would somehow blur the result. I am happy to be corrected if I am wrong.

A blurry 8 ( or is it an 8? or a 3? or a B?) would make me squint and possibly double check the original just to make sure.

A perfectly clear 8 would make me assume it is an 8 which was born as an 8, and I would just go ahead taking it as good.

And "The normal quality option produces small file sizes by using advanced compression techniques. Image quality is generally acceptable, however, text quality degradation and character substitution errors may occur with some originals."

If you are making a copy, it means that you are printing it and you don't care about the resulting file which will be deleted once you are done with it ( again, an assumption which can be corrected by anyone in the know ). Even if it turns out to be 300MB, do you really care?

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Re: 'this is simply unacceptable'

With an old analog copier when its dpi was too low for the type face, the output was hard to read.

The problem is that this copier is producing output that looks high-quality, but is not. This is unacceptable, the setting should not be on the copier, or it should add random dots to the output so it looks how quality.

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Re: 'this is simply unacceptable'

These workcentres ARE scanners and printers. They have a copy function which is really "scan to temp and print out" and if you remove that, there will be riots.

..and now I have to grumble around checking we don't have any affected models.

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Re: 'this is simply unacceptable'

I agree.

As an ex-field tech for Xerox, I came across a number of problems that occurred simply because people were not willing to RTFM.

I'm willing to bet in this case, the guy in question was feeding the paper through the ADF. While it is the fastest method, it can be prone to these sorts of mistakes due to small fonts, paper slippage due to not using the paper guides, crap on the glass (people dont clean the 1 inch wide glass strip thats used when the ADF is operated, only the large sheet), worn feed rollers, and so on.

If you want good quality copies, then take the time to use the manual option, and make sure that the resolution setting is adequate for your needs.

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Facepalm

This reminds me of Jimbo & The Set Jet back in 80's kids TV land...

"The premise of the cartoon is that Jimbo was originally intended to be a Jumbo Jet, but his designer could not tell the difference between inches and centimetres, resulting in his diminutive size"

http://en.wikipedia.org/wiki/Jimbo_and_the_Jet_Set

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FAIL

Re: Aircraft designers

Photocopies do go up to A0, it is just you are not used to such machines.

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Goes up to 11

Maybe Spinal Tap could have blamed their Stonehenge on this.

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Facepalm

@MrDamage

As an ex-field tech for Xerox, I came across a number of problems that occurred simply because people were not willing to RTFM.

It may come as a surprise to you to learn that most people in offices have more important things to do than read photocopier manuals.

Once upon a time the photocopier was a vital piece of office equipment, and people used it often enough to know how it worked, though I don't suppose they read the manuals, even then. With the reduction in paper documents, an average person might make one photocopy a month. Meanwhile, the copiers have become much more complicated.

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Anonymous Coward

Re: Aircraft designers

This is correct, but the article was about office copiers. The A0 machines are very different and are designed to handle engineering drawings. Whether you use a Kyocera or Xerox A0 machine won't make any difference, contrary to the suggestion of the GPP.

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Anonymous Coward

Re: 'this is simply unacceptable'

Yes, on further thought I agree this is a legitimate objection, and actual numeric substitution should never occur.

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Silver badge

Re: if not a printer combined with a high quality scanner?

Yes that's what they are these days. But that's not what copiers were when they first came out. Back then you were bouncing a light beam off the paper onto a photoptically sensitive rotating drum that eventually transferred toner/ink to the page. It might smudge, but then the characters were illegible and you had to confirm the numbers or use a better original. More to the point, the data corruption was immediately obvious at least to the consumer.

When we switched to the scanner/printer model because it was more useful and cost effective, it was under the assumption it produced the same sort of output. But what is apparently happening is that the system uses some sort of sample or dynamic image storing and compression that results in CHANGING THE DATA. Were I on a jury in a death or injury case and Xerox hauled out that disclaimer I'd triple the damages for vexation.

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Anonymous Coward

Re: I've used these copiers...

You know Anthony, this is how you got in trouble the first time. Now, please return to your twitter account instead of bothering us here.

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Unhappy

Re: @ Jolyon Smith - 'this is simply unacceptable'

Re "bad design"

Indeed. At a minimum the copier should flash a warning message to users when settings are down to the 'questionable' range. Although even trained and experienced users such as the Asiana pilots of Flight 214 will ignore warnings.

Against stupidity even the Gods contend in vain.

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Pirate

@Tom 13

Quite right, and also the current scanner/printer copiers (and especially those networked as printers) write everything to internal disc drives, where the documents stay, potentially for years. When the copier/printer is sold on, those documents remain with the device opening a security gap of huge proportions.

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Anonymous Coward

@ AC 0735 GMT - Re: "I've worked for Xerox for some years"

You should see what happens when those labels go through the fuser (that's the hot high pressure bit, for readers who aren't aware). Or when OHP foils (remember them?) of the inkjet kind go through the fuser. I've seen that, because I'm out there on the same planet as the copier users. What planet are you on?

I'm actually on this planet. And while your post makes you look clever it also shows a certain lack of credibility. Labels print just fine on lasers (personal experience on a variety of printers from Workcentre 315 to DP6180 and DC 7000 to iGen3); it's the FreeFlow 665 scanners that eat them in the ADF's inverter.

Transparencies (or OHP foils, as you like to call them) also work just fine.

My grunge is with users that put their fingers on buttons that have a "Here be dragons" warning and then complain about dragons being there. But I have to agree on one point now that I have seen all the responses: The option to switch down from HQ needs to go completely.

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FAIL

Re: "I've worked for Xerox for some years"

I "LOVE" calls for inkjet paper/OHP film etc melted in the fuser. Such a blatent PEBKAC is always chareable.

But back to the article . . . 200DPI for point size 6 ??? And this guy's dong a PHD ?

Hey, I need to copy this detailed thing, I know I'll turn down the DPI to make the file smaller.

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Re: @MrDamage

Sure, people might have more important things to do than read the manual. But that does not exempt them from actually thinking for half a second.

All companies try to make their equipment idiot proof. The only problem is that the Universe immediately responds by creating a bigger idiot.

And for the record, photocopiers have only become more complicated at the back end. The front end has become so simplified that any moron can use it. Unfortunately, many of them do.

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Joke

Re: @ Jolyon Smith - 'this is simply unacceptable'

>There's a warning in the manual, if anyone could ever bother to read it, about small fonts and compression.

Yes, you are right. It's there. In small print, of course.

What the warning says is 'Small fonts are impeccable for use in documents requiring accuracy.'

When instead it should say, and does so when printed in a larger font, 'Smalls fonts are impossible for use in documents requiring accuracy.' (The original documentation was in Japanese or some other exotic language from west of Greenwich...)

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Mushroom

Re: @MrDamage

>It may come as a surprise to you to learn that most people in offices have more important things to do than read photocopier manuals.

Yeah, like get that shredder repaired because somebody tried to shred something with a paper clip on it, which they wouldn't have done hadn't they had to perform a fire drill when they needed time to read the effing manual for the shredder...

We actually had a fire in our office and nobody got up to leave, because we hadn't been told that there was a drill scheduled for that day.

Office people who don't RTFM...bane...of...their...own...lives...

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Why do you need to compress *copy* data? Scan, OCR, etc. makes sense, but copies? They're just getting spit back out.

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They are held in memory

When you copy a 200page doc it scans it, copies it into RAM then does any 2-up, half side, 2 sided reshuffling, then sends it to the laser printer - which is what a modern copier is

Some copiers also let you select extra copies of earlier docs.

there is normally a security scare story every week about how to access old copies - which is why most companies keep a separate machine for HR/ Financials etc

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They are held in memory

What's wrong with lossless compression, like LZW? Memory is cheap and data buses are fast these days.

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Anonymous Coward

There's all sorts of image processing going on in there

the CCDs used in scanners are RGB devices which have to apply various white balance and hue corrections and, ideally, identify information-free areas over which background suppression will be run, then the image data has to be converted to CMYK before it's rasterised and handed over to the print engine for output. The rasterised dataset is reused for additional copies, so it has to be shunted into and retrieved from storage. Even black text will be captured in RGB space and then converted, and that's before we get into the wriggles of machines which output that as single or four-colour black. Regardless of the actual rated speed of the engine, users want their copy as quickly as possible once they hit the button, so any and all shortcuts that can be taken to minimise the time the machine spends working upon image data or shunting it around are seen as fair game.

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Trollface

Re: They are held in memory

Additionally, there is black magic to interdict the copying of banknotes. And possible child porn and back issues of "Insipre".

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Anonymous Coward

Re: There's all sorts of image processing going on in there

"any and all shortcuts that can be taken to minimise the time the machine spends working upon image data or shunting it around are seen as fair game."

If you're in marketing, maybe.

As a user and potential purchaser, I want a copier to copy. Accurately.

If the copy isn't good enough, and I've paid loadsamoney, I'd like a button that says "enhance" and one that says "SmartCopy" and maybe one that says "make Whheeeee noise"

What I don't want is a photocopier that silently and invisibly and undetectably changes the content of my copy without telling anyone.

That's not a photocopier, that's a class action in waiting.

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Trollface

Re: They are held in memory

The 'Black magic' is called the Eurion constellation. I've always wondered if it's free to use or copyright (no pun intended)... I may have slipped it into random work reports for fun.

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Re: There's all sorts of image processing going on in there

Our copier had a "make Whheeeee noise" button. A big green one... service guy came the next day...

I can just guess what would happen if we lost out on a RFC because the copier had changed a 6 to an 8.

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Bank notes

If the copier can recognise what money looks like and refuse to copy it, then it should be able to recognise text and not interfere with it. But then, I don't know how it does it for money. Something like a bar code to be recognised?

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Anonymous Coward

Re: Bank notes

look for a pattern of small yellowish rings on the note, it's that. on the UK Elgar 10 quid note it was hidden in the musical notes :)

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Unhappy

Re: There's all sorts of image processing going on in there

"I can just guess what would happen if we lost out on a RFC because the copier had changed a 6 to an 8."

Perhaps you already have?

Time for a visit to Messrs Shyster, Shyster and Flywheel?

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Anonymous Coward

Re: They are held in memory

Sadly I'm quite familiar with the JBIG2 compression used here. It's a bilevel compression scheme (ie for 1-bit black & white images only) which can give quite significant improvements over CCITT group 4, which is the predecessor - LZW isn't used here, it's better for general compression but for bi-level images CCITT and (now) JBIG2 are hard to beat. As an example, Ar at 200 DPI you might be looking at about 30-40KB for a page of text, maybe 60% of that for JBIG2 and much more for LZW, JPEG or any other non-specialized schemes.

The JBIG2 spec is a nightmare of options, but one core part of it is the pattern matching, where it looks for repeated symbols and replaces them with a lookup in a table. Clearly that pattern match algorithm isn't working here. The other nasty part about the spec is it specifies a decoder ONLY - an encoder is simply expected to generate a document that can be decoded by a decoder matching the spec. So lots of room for error for implementers.

However the one thing I can say for sure is saying this is a user error is incorrect. The pattern matching is one of many compression options in the algorithm and it doesn't have to be used. If the resolution is too low (implying the pattern cannot be matched with a suitable degree of accuracy) the algorithm should fall back to a regular CCITT-style compression. Whoever wrote the algorithm has clearly set the confidence level incorrectly.

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Bronze badge

Re: They are held in memory

Thank you, that was clear and informative and deserves an extra fifty up votes.

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This comment withdrawn.

Anonymous Coward Posted Wednesday 7th August 2013 12:37 GMT

has much better insight and hopefully a workable solution.

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Not just copiers

A CFO stood up at a board meeting once and congratulated us on a 320,000 quid sale

We had to point out that this was "A3 20,000" where A3 is how the email had decided to print the GBP sign

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