SWMBO complained that one of the printers (LJ6p) was "broken".

Hmmm... not out of paper. DNS is up so it's not a name resolution
error. "RESET" doesn't recover.

Cycle power. OK, appears fine. Print a page and all is well.

A few minutes later, the same complaint! Printer is in the same
hung state.

Apparently, she is trying to print the third page of a PDF I'd made for
her. PDF is three scanned images (tax form + copy of personal check).
Printer is very upset with the check image!

Hmmm... maybe there is some collusion between printer manufacturer
and banking industry to ensure folks can't print checks? But, this
is an old printer -- introduced in '96, discontinued in '99. So,
any kabitzing had to predate that!

Closer examination of the check (scanned image) shows it comprised of
lots of little dots. I wonder if they are just relying on "too much
data" as a means of hanging the printer?

(She doesn't need to print a hardcopy of the check as long as she
keeps the PDF image so that's not an issue)

Anyone have any insights to this? Jeff?

On 8/6/21 9:03 PM, Don Y wrote:
> Anyone have any insights to this?

I've run into this a few times over the years.

The first thing that I would try is reducing the DPI that I'm trying to
print at. Maybe reduce the number of colors.

Almost every single time the problem came from the data being too
complex for the printer to process /in/ /a/ /timely/ /manner/ thus
tickling a timeout somewhere (printer, printer driver, communications
between the two, etc.)

It sounds like you / she might be only printing one page, but if you're
printing the entire document, try printing one page at a time.

--
Grant. . . .
unix || die

On 8/6/2021 10:15 PM, Grant Taylor wrote:
> On 8/6/21 9:03 PM, Don Y wrote:
>> Anyone have any insights to this?
>
> I've run into this a few times over the years.

"In general"? Or, when trying to print things that probably might not want
to be printable?

[I wonder what would happen if I tried to scan a dollar bill and then
print *that*!]

> The first thing that I would try is reducing the DPI that I'm trying to print
> at. Maybe reduce the number of colors.

Monochrome printer. I am assuming the image sent to the printer (by the
driver) is monochrome -- so the chroma was shed *by* the driver.

[I can try to verify this by converting the image to black-and-white
in Photoshop]

> Almost every single time the problem came from the data being too complex for
> the printer to process /in/ /a/ /timely/ /manner/ thus tickling a timeout
> somewhere (printer, printer driver, communications between the two, etc.)

No, this hung the printer *hard*. I had to cycle power to get it
to recover. "RESET" did nothing.

> It sounds like you / she might be only printing one page, but if you're
> printing the entire document, try printing one page at a time.

Printer has 66MB of memory. She's only printing that page -- which is
just a *check* (small).

I'm going to try the monochrome version. Then apply a gaussian blur to
the entire image (in the hope of driving some of those little dots
below the "black" threshold).

I may also try cropping the image to see if there is a portion
that tickles the printer the wrong way.

This is just interesting; I've never tried to print a check image
(nor paper currency!) before so it's a learning experience...

On 8/6/2021 10:58 PM, Don Y wrote:
> This is just interesting; I've never tried to print a check image
> (nor paper currency!) before so it's a learning experience...

Hmmm... *this* might shed some light (if true; I'll have to inspect
the document more carefully).

<https://www.scienceabc.com/eyeopeners/cant-photocopy-scan-currency-notes.html>

It also suggests that Photoshop would choke on it -- so I'll have to try
that, as well.

(Yet the scanner had no problem offering up the image!)

On 8/6/2021 11:06 PM, Don Y wrote:
> On 8/6/2021 10:58 PM, Don Y wrote:
>> This is just interesting; I've never tried to print a check image
>> (nor paper currency!) before so it's a learning experience...
>
> Hmmm... *this* might shed some light (if true; I'll have to inspect
> the document more carefully).
>
> <https://www.scienceabc.com/eyeopeners/cant-photocopy-scan-currency-notes.html>

Yup. The check has this pattern of dots on it -- camouflaged as a decorative
pattern.

This is wonderful! It suggests that you can create "copy-proof" documents
by including this sort of pattern!

Of course, GENERATING them (on your own) would be impossible. But, the
folks who print the checks obviously can do so! You could then make
COA's et al. and be assured they were genuine.

This assumes, of course, that it is legal for a print shop to print
this pattern on NON CURRENCY images... No doubt you'd need a traditional
printer (with a *press*) and not a "e-printer" (who would likely have the
same limitations that you would).

Now, will *every* print shop know of such restrictions, if they exist?
Or, will I have to find a "big" print shop and hope they have their own
"legal" department to keep them apprised of these sorts of things... ?

On 07/08/2021 04:03, Don Y wrote:
> SWMBO complained that one of the printers (LJ6p) was "broken".
>
> Hmmm... not out of paper.  DNS is up so it's not a name resolution
> error.  "RESET" doesn't recover.
>
> Cycle power.  OK, appears fine.  Print a page and all is well.
>
> A few minutes later, the same complaint!  Printer is in the same
> hung state.
>
> Apparently, she is trying to print the third page of a PDF I'd made for
> her.  PDF is three scanned images (tax form + copy of personal check).
> Printer is very upset with the check image!

Same will happen if you try to print your own banknotes too!
(many scanners will refuse point blank to scan them)

> Hmmm... maybe there is some collusion between printer manufacturer
> and banking industry to ensure folks can't print checks?  But, this
> is an old printer -- introduced in '96, discontinued in '99.  So,
> any kabitzing had to predate that!
>
> Closer examination of the check (scanned image) shows it comprised of
> lots of little dots.  I wonder if they are just relying on "too much
> data" as a means of hanging the printer?

Can't be that since these days in the UK you print your own insurance
certificate and they are essentially the same sort of anti copy style
with large numbers of dots in the background so that a scan with have
moire fringes. I'm surprised a printer that old can do it.

I have only seen it happen with fairly modern 2010 onwards all in ones.

> (She doesn't need to print a hardcopy of the check as long as she
> keeps the PDF image so that's not an issue)
>
> Anyone have any insights to this?  Jeff?

--
Regards,
Martin Brown

On 8/7/2021 12:24 AM, Martin Brown wrote:
> On 07/08/2021 04:03, Don Y wrote:
>> SWMBO complained that one of the printers (LJ6p) was "broken".
>>
>> Hmmm... not out of paper. DNS is up so it's not a name resolution
>> error. "RESET" doesn't recover.
>>
>> Cycle power. OK, appears fine. Print a page and all is well.
>>
>> A few minutes later, the same complaint! Printer is in the same
>> hung state.
>>
>> Apparently, she is trying to print the third page of a PDF I'd made for
>> her. PDF is three scanned images (tax form + copy of personal check).
>> Printer is very upset with the check image!
>
> Same will happen if you try to print your own banknotes too!
> (many scanners will refuse point blank to scan them)

I hypothesize that the scanner was able to process the image.
And, the image embedded in the PDF "correctly".

Further, that the PDF "print" routine *and* the printer's driver
were able to deliver the image to the printer.

And, that it was the printer than crashed when given that image.

If the scanner had coughed on the image (but not CHOKED), then everything
after that point would be printable, though potentially subtly altered.

Likewise, if making the PDF is where the problem was introduced,
then it would have complained *or* the printer would have produced
something "subtly altered".

The fact that the printer tried to print <something> and then
hung suggests the fault was its own doing.

This also makes sense when you consider that all of these other
steps could have been accomplished with FOSS software -- the internals
of which are visible for inspection. The only step that can't be
emulated/synthesized is the actual marking engine.

I.e., no matter how I generate the image sent to the printer,
the printer has the final say in whether or not to actually
generate the output.

>> Hmmm... maybe there is some collusion between printer manufacturer
>> and banking industry to ensure folks can't print checks? But, this
>> is an old printer -- introduced in '96, discontinued in '99. So,
>> any kabitzing had to predate that!
>>
>> Closer examination of the check (scanned image) shows it comprised of
>> lots of little dots. I wonder if they are just relying on "too much
>> data" as a means of hanging the printer?
>
> Can't be that since these days in the UK you print your own insurance
> certificate and they are essentially the same sort of anti copy style with
> large numbers of dots in the background so that a scan with have moire fringes.
> I'm surprised a printer that old can do it.
>
> I have only seen it happen with fairly modern 2010 onwards all in ones.

I recall when the original color Xeroxes came out, there was some mechanism
to prevent copying currency. There are rules governing any such reproductions
(primarily concerning size -- you have to make the results much larger or
smaller than normal currency). Recall in the US, all bank notes are the
same size -- and all green/black ink. None of those pink or blue notes
you're so fond of! :>

[Our cashier's office, at school, was wallpapered with a grossly enlarged
image of a dollar bill -- like 8 ft tall!]

But, I wasn't aware that the same sorts of protections were present in
*checks*. And what else?

There has to be some prohibition on printing (by any means!) that pattern,
even if an "original document" -- lest someone include that pattern in
an image of a check, etc. So, where are those rules enforced? Are there
printing police that examine every wedding invitation, restaurant menu,
COA (!), magazine article, concert ticket, etc. looking for the magic dots?

Assuming you aren't printing something that remotely resembles currency
(or promisory instruments), this seems like a great way to ensure authenticity.

"Is this an original, unaltered copy of your last will and testament?"

"Is this a legitimate property title?"

etc.

<https://en.wikipedia.org/wiki/EURion_constellation>

This is delightful! I learned something completely unexpected, today!

On 07/08/2021 18:13, Don Y wrote:
> <https://en.wikipedia.org/wiki/EURion_constellation>
>
> This is delightful!  I learned something completely unexpected, today!

I hear that Bobby Tables now has EURions tattooed on his face.