Subject: [IPP] Fwd: Value of "printer-resolution" | "printer-resolution-supported" vs. the "pwg-raster-resolution-supported"?

From: Ira McDonald <[email-masked]>
Date: Sun, 24 Jul 2016 12:39:57 -0400

---------- Forwarded message ----------
From: Kennedy, Smith (Wireless Architect) <[email-masked]>
Date: Wed, Jul 13, 2016 at 4:00 PM
Subject: Value of "printer-resolution" | "printer-resolution-supported" vs.
the "pwg-raster-resolution-supported"?
To: Michael Sweet <[email-masked]>, Ira McDonald <[email-masked]>

Hi there,

What again is the value of "printer-resolution" and
"printer-resolution-supported" vs. the document format specific attributes
that seem to specify the same information
("pwg-raster-resolution-supported", etc.)?  I know that
"printer-resolution" | "printer-resolution-supported" were defined in RFC
2911 but I'm trying to explain their value to some folks here and I'm at a
loss.

Thanks for any help!

Smith

/**
    Smith Kennedy
    Wireless Architect - Client Software - IPG-PPS
    Standards - IEEE ISTO PWG / Bluetooth SIG / Wi-Fi Alliance / NFC Forum
/ USB IF
    Chair, IEEE ISTO Printer Working Group
    HP Inc.
*/
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---

From: Ira McDonald <[email-masked]>
Date: Sun, 24 Jul 2016 12:40:49 -0400

---------- Forwarded message ----------
From: Michael Sweet <[email-masked]>
Date: Wed, Jul 13, 2016 at 5:02 PM
Subject: Re: Value of "printer-resolution" | "printer-resolution-supported"
vs. the "pwg-raster-resolution-supported"?
To: Smith Kennedy <[email-masked]>
Cc: Ira McDonald <[email-masked]>

Smith,

> On Jul 13, 2016, at 4:00 PM, Kennedy, Smith (Wireless Architect) <

printer-resolution specifies the output resolution.  For example, a printer
that supports 4800x1200dpi can allow that resolution to be selected for
higher quality output.

pwg-raster-resolution-supported specifies supported document resolutions,
which are typically some integer divisor of the
printer-resolution-supported values.  For example, that same printer might
advertise 300dpi and 600dpi PWG Raster resolutions, which are upscaled to
4800x1200dpi (or whatever printer resolution is in use).

Having a lower document resolution allows for faster transfer (and less
processing on the printer overall) while still supporting high resolution
output.  And typically you are getting RGB or grayscale data that needs to
be converted to the device color space, dithered, etc.

_________________________________________________________
Michael Sweet, Senior Printing System Engineer
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---

From: Ira McDonald <[email-masked]>
Date: Sun, 24 Jul 2016 12:42:07 -0400

---------- Forwarded message ----------
From: Kennedy, Smith (Wireless Architect) <[email-masked]>
Date: Wed, Jul 13, 2016 at 5:13 PM
Subject: Re: Value of "printer-resolution" | "printer-resolution-supported"
vs. the "pwg-raster-resolution-supported"?
To: Michael Sweet <[email-masked]>
Cc: Ira McDonald <[email-masked]>

Ah, so it is the difference between the input document format content
resolution and the resolution the Printer or language interpreter should
use for the output. I can see how that might be useful for vector formats
because that might factor into the output speed or marking agent usage.

But for raster document formats, if you send a lower resolution, upscaling
cannot "create" information, so you would still end up with the source
resolution, right?  (I'll discuss this with our language interpreter /
color science people...)

Smith

> On 2016-07-13, at 3:02 PM, Michael Sweet <[email-masked]> wrote:
>
> Smith,
>
>
> printer-resolution specifies the output resolution.  For example, a
printer that supports 4800x1200dpi can allow that resolution to be selected
for higher quality output.

---

From: Ira McDonald <[email-masked]>
Date: Sun, 24 Jul 2016 12:42:53 -0400

---------- Forwarded message ----------
From: Michael Sweet <[email-masked]>
Date: Wed, Jul 13, 2016 at 5:47 PM
Subject: Re: Value of "printer-resolution" | "printer-resolution-supported"

Smith,

> On Jul 13, 2016, at 5:13 PM, Kennedy, Smith (Wireless Architect) <
>
> But for raster document formats, if you send a lower resolution,
upscaling cannot "create" information, so you would still end up with the
source resolution, right?  (I'll discuss this with our language interpreter
/ color science people...)

You can't make the equivalent of vector quality, no, but "resolution
enhancement technology" has been a staple of laser printers for years to
improve the effective resolution when printing.  Also, most printers do not
produce 255 different sizes of dots so you "lose" some resolution in the
printer due to dithering/halftoning.

As far as edge detail you can see a greater improvement between 300 and 600
DPI than (say) 600 and 1200 DPI thanks to the limits of visual acuity - at
that point the dots are so small you are better off using the higher
resolution to improve shading/dithering than getting a smoother looking
line/character.  Thus, the document resolution can be 600DPI while the
output resolution is a much higher resolution.