[Printing-summit] Printer/driver testing and certification

Stark, Jens Jens.Stark at seeg.sharp-eu.com
Mon Aug 21 04:46:45 PDT 2006

Robert wrote:

>We received a lot of complaints late in the Gutenprint 5.0 cycle about
>CD's printing slightly "squashed" on a lot of printers, due to a
>design decision we had made in the CUPS driver for how to handle full
>bleed capable printers.  This would easily have passed the "some
>output was created" test, but it wasn't meeting users' needs.

>On a more basic level, we've had plenty of bugs involving something
>that certainly created output, but the output was completely incorrect
>for the printer in question -- the printer might or might not print
>anything, or spit out paper, or it might work in color mode but not
>black and white.  Realistically, somebody's going to have to evaluate
>the output to decide whether the test passes or not.

>Testing photo printers opens an even bigger can of worms.  People will
>have certain expectations of color fidelity.

>Based on the discussion in Atlanta, I think it will probably be
>easiest to test business-oriented use cases than "artistic" use

Ooookay.. There are a number of different classes of printers.

And different use cases.

Let me give you an example :

I use a couple of different printers, for different needs.

One Brother QL-500 for label printing.

One Canon Pixma 4200 for home CD labelling and the odd page of text.

Job-related stuff is of course printed at work, where there are things like=
 a 70ppm A4 capable mono printer that can make brochures, staple and punch =
paper and it's slower brother that can do color.

One set of requirements will never fit them all.

But f=FCr A4 capable printers and up, something like "Print the CUPS test p=
age" is at least a start.

When it comes to quality... How do good color printouts look ? Spectrometri=
cally correct ? Sharp ?
This is not easy to decide, even for the experts. =

So there is no serious way of determining if a color printer "works" well i=
n photo printing.

There are also a number of tests for the hardware bit.

Here is a good example of a stress test :


But - is hardware quality something to worry about ? =

Usually, the manufacturer is concerned with providing the best possible qua=
lity (really, they are!).

Quality isn't always the same, even under Windows.
(One could print a page using the Windows driver, then using a CUPS driver.=
 Do they look the same ? Same quality at least ? :) )

What CAN be tested (usually by the manufacturer) are the following :

- is the printer working ?
- reliably ?
- without empty pages ?
- is the printout "correct" ? (Does it match reasonable expectations?)
- Is the printer locking up ? (A no-no)

I would love to see a set of sample originals and printing instructions for=
 each class of printer.
Any manufacturer or user could download a set, print it and claim complianc=
e or non-compliance.
"The Hogwash 23-40A will print the office files fine, but when printing the=
 large size photos, you need extra RAM or it will crash."
This is what linuxprinting.org is about - all it needs (maybe!) is a slight=
ly more "formal" approach.

And a manufacturer who claims compatibility with the test suite will gladly=
 tell the world about it.

Would they lie ? Unlikely. The loss in reputation would be massive.


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