Subject: [IPP] More Discussion on bi-level, mono-chrome and color

From: "Petrie, Glen" <[email-masked]>
Date: Mon, 18 Apr 2011 11:38:52 -0700

Can we change the required on mono to optional and bi-level be required.

Bi-level           required for any printer

Color               required is color printer

Mono              1 toner - optional 

Mono              >2 toners - optional

And the other is the table are optional

Basically mono is a dithering of a single-color to produce an output
from saturation to white.  But dithering is a fancy thresholding
(bi-level); so there is no need to actually specify it as required or
optional since it will be encompassed by the printer type (b/w or
color).  For the case where a user wants single toner mono-chrome, it is
should be a capability of the printer that is support that function and
not be mandated that all printers must support it.   In other words it
may be a requirement of the user but not a support capability of a
printer.  That can be said about many printing functionalities. 

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From: Michael Sweet <[email-masked]>
Date: Mon, 18 Apr 2011 13:37:52 -0700

On Apr 18, 2011, at 11:38 AM, Petrie, Glen wrote:
> Mono              1 toner – optional
> Mono              >2 toners – optional
> Basically mono is a dithering of a single-color to produce an output from saturation to white.  But dithering is a fancy thresholding (bi-level);

I don't agree with this. Thresholding is not dithering, which by definition adds noise to the signal (in this case 2D color arrays) in order to more accurately portray the signal given limited output capabilities. The usage here is not to describe a particular algorithm but rather to specify intent: high contrast black and white output. You'd use this mode when scanning and printing forms, for example. (Oops - time for another thread...) It is pretty clear I need to convert Table 2 to a list of paragraphs describing the keywords and their meanings in detail.

The current requirements map to use cases - color and grayscale (monochrome) printing are required for our current use cases. "Bi-level" is not, although it is something we should consider for the scanned forms use case. We can continue to debate the requirements, but every OS and just about every driver for a color printer includes UI to print color as grayscale... If the intent is to allow a limited mobile client to do the same, we need to ask the printer to help out, and we can decide whether that means 1-color or process (N-color, N>1) black.

________________________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair

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From: "Petrie, Glen" <[email-masked]>
Date: Mon, 18 Apr 2011 13:57:03 -0700

Ok, we have a differing understanding of some of the image processing
involved in printing.  While I still disagree, I agree to disagree and
will let the group decide the matter. 

________________________________

From: Michael Sweet [mailto:[email-masked]] 
Sent: Monday, April 18, 2011 1:38 PM
To: Petrie, Glen
Cc: [email-masked]
Subject: Re: [IPP] More Discussion on bi-level, mono-chrome and color

	Can we change the required on mono to optional and bi-level be
required.

	Mono              1 toner - optional

	Basically mono is a dithering of a single-color to produce an
output from saturation to white.  But dithering is a fancy thresholding
(bi-level);

I don't agree with this. Thresholding is not dithering, which by
definition adds noise to the signal (in this case 2D color arrays) in
order to more accurately portray the signal given limited output
capabilities. The usage here is not to describe a particular algorithm
but rather to specify intent: high contrast black and white output.
You'd use this mode when scanning and printing forms, for example. (Oops
- time for another thread...) It is pretty clear I need to convert Table
2 to a list of paragraphs describing the keywords and their meanings in
detail.

The current requirements map to use cases - color and grayscale
(monochrome) printing are required for our current use cases. "Bi-level"
is not, although it is something we should consider for the scanned
forms use case. We can continue to debate the requirements, but every OS
and just about every driver for a color printer includes UI to print
color as grayscale... If the intent is to allow a limited mobile client
to do the same, we need to ask the printer to help out, and we can
decide whether that means 1-color or process (N-color, N>1) black.