[comp.lang.postscript] what about color laser printers?

deke@valhalla.ee.rochester.edu (12/09/88)

In article <6385@pogo.GPID.TEK.COM> curtj@pogo.GPID.TEK.COM writes:
>In article <4338@homxc.UUCP> mlm@homxc.UUCP writes:
>>Does anyone out there use or know of a color slide or transparency machine
>>that knows PostScript.
>
>	Tektronix Phaser CP.  It was announced at COMDEX.. It's a 300 DPI
>	color printer with both a Color PostScript Compatible interpreter as
>	well as an HPGL interface.  It can print on both paper and trans-
>	parencies.
>
>	At this point in time, it requires a PC and an expansion board,
>	which fits into the PC.

Sounds like the "Color PostScript Compatible interpreter" is on the PC board.
Is that right?  What about a *color* output device that like a LaserWriter, 
interprets PostScript onboard?  Not an ink-jet or a color thermal transfer,
but a Cannon-engine type device.  Do they exist?

It seems to me that there is a sizeable market out here waiting for the "right"
solution.  Is there anyone from Adobe, Cannon, or Apple listening that would 
care to comment?

      ^Deke Kassabian,   deke@ee.rochester.edu   or   ur-valhalla!deke
   Univ of Rochester, Dept of EE, Rochester, NY 14627     (+1 716-275-3106)

prc@ERBE.SE (Robert Claeson) (12/12/88)

In article <1667@valhalla.ee.rochester.edu>, deke@valhalla.ee.rochester.edu writes:

> Sounds like the "Color PostScript Compatible interpreter" is on the PC board.
> Is that right?  What about a *color* output device that like a LaserWriter, 
> interprets PostScript onboard?  Not an ink-jet or a color thermal transfer,
> but a Cannon-engine type device.  Do they exist?

The QMS ColorScript color PostScript, 300 dpi printer.
-- 
Robert Claeson
ERBE DATA AB
rclaeson@ERBE.SE

richard@gryphon.COM (Richard Sexton) (12/16/88)

In article <427@maxim.ERBE.SE> prc@ERBE.SE (Robert Claeson) writes:
>In article <1667@valhalla.ee.rochester.edu>, deke@valhalla.ee.rochester.edu writes:
>
>> interprets PostScript onboard?  Not an ink-jet or a color thermal transfer,
>> but a Cannon-engine type device.  Do they exist?

Yes, but you cant buy them yet. Be patient.

>The QMS ColorScript color PostScript, 300 dpi printer.

Nope. It's thermal transfer.


-- 
               ``Wake me up when it's time to go to sleep''
richard@gryphon.COM   {...}!gryphon!richard   gryphon!richard@elroy.jpl.nasa.gov

jackson@adobe.COM (Curtis Jackson) (12/18/88)

}In article <6385@pogo.GPID.TEK.COM> curtj@pogo.GPID.TEK.COM writes:
}>	Tektronix Phaser CP.  It was announced at COMDEX.. It's a 300 DPI
}>	color printer with both a Color PostScript Compatible interpreter as
}>	well as an HPGL interface.  It can print on both paper and trans-
}>	parencies.

Just a bit of picky education:  There is no such thing as "Color Postscript".
The Postscript [tm] Language from Adobe has always had full color support
from Day 1.  How the Postscript interpreter on a given printer chooses to
implement (or not implement) color-related Postscript operators is another
matter altogether...

Curtis Jackson @ Adobe Systems in Mountain View, CA  (415-962-4905)
Internet: jackson@adobe.com	uucp: ...!{decwrl|sun}!adobe!jackson
Q
-- 

Curtis Jackson @ Adobe Systems in Mountain View, CA  (415-962-4905)
Internet: jackson@adobe.com	uucp: ...!{decwrl|sun}!adobe!jackson

jmr@nada.kth.se (Jan Michael Rynning) (12/19/88)

In article <113@adobe.COM> jackson@adobe.UUCP (Curtis Jackson) writes:
>The Postscript [tm] Language from Adobe has always had full color support
>from Day 1.

Then the colour operator extensions added after Day 1 must have given
the PostScript language an overfull colour support.

Jan Michael Rynning,			jmr@nada.kth.se
Department of Numerical Analysis	If you can't fully handle domains:
  and Computing Science,		ARPA: jmr%nada.kth.se@uunet.uu.net
Royal Institute of Technology,		UUCP: {uunet,mcvax,...}!nada.kth.se!jmr
S-100 44 Stockholm,			BITNET: jmr@sekth
Sweden.					Phone: +46-8-7906288

rainero@rocksanne.UUCP (Emil Rainero) (12/19/88)

In article <113@adobe.COM> jackson@adobe.UUCP (Curtis Jackson) writes:

>Just a bit of picky education:  There is no such thing as "Color Postscript".
>The Postscript [tm] Language from Adobe has always had full color support
>from Day 1.

THIS IS NOT TRUE. Synthetic graphics (yes fonts too) could use setrgbcolor and
sethsvcolor operators, but there was no way to send color images (jee, maybe 
this is why the new operator is called 'colorimage') to 1.0 PostScript printers.


The extensions for color also include a CMYK color model, color screens,
color transfer functions, and support undercolor removal and black generation.
My main reason for posting this message is to make clear that while it is true 
that color was supported from PostScript's inception, additions were necessary
to claim functional color support. These extensions, as well as other problems
that Apple has introduced, is why we are now seeing device specific PostScript 
masters being generated from Macintosh emitters.


(Emil's Psychic Forecast for 1989)
It is interesting to note that even with 24 or 32 bit color images, there is
no built-in support for compression. (please, no flames about writing it in
PostScript). With the proliferation of compression/decompression chips,
I would expect to see further extensions from Adobe.


-- 
Emil Rainero -- Xerox Webster Research Center
UUCP:           {seismo,allegra,decvax,cmcl2,topaz}!rochester!rocksanne!rainero
Arpa Internet:   Rainero.wbst@xerox.arpa

rcd@ico.ISC.COM (Dick Dunn) (12/20/88)

In article <113@adobe.COM>, jackson@adobe.COM (Curtis Jackson) writes:
> Just a bit of picky education:  There is no such thing as "Color Postscript".

True as far as anything I've ever seen...however...
> The Postscript [tm] Language from Adobe has always had full color support
> from Day 1...
...seems at odds with what Adobe has done recently...

I have a document, allegedly from the Adobe PostScript file server, called
_Color_Operator_Definitions_, dated April 25, 1988 and copyrighted 1988 by
Adobe Systems Incorporated, which claims:
    
    The PostScript language will be upgraded to support color more fully by
    a variety of means...
    ...The PostScript language currently supports color to a limited
    extent...
    ...To support color printing completely, however, a few additional
    operators need to be added to the PostScript Language to fill the
    gaps...

The gist of it is that the original definition of PostScript has operators
for producing color images of certain types, in certain ways.  However, for
other needs, it may be very difficult and/or require multiple passes.  The
obvious limitation is that the `image' operator cannot render a color
image.  To do so, it needs multiple screens (3 or 4, depending on the color
model used) and pixel values for each screen.

I think the grandparent article (to which Jackson responded) was probably
(mis)using the term "Color PostScript" to mean "PostScript upgraded with
the color image operators."  It *would* be nice to have a concise term to
describe this level of revision of PostScript, although I agree with
Jackson that "Color PostScript" isn't right because PostScript already had
color-handling concepts.
-- 
Dick Dunn      UUCP: {ncar,nbires}!ico!rcd           (303)449-2870
   ...Worst-case analysis must never begin with "No one would ever want..."

jacks@pogo.GPID.TEK.COM (Jack Slingerland) (12/21/88)

Curtis Jackson (jackson@adobe.COM) states:

> Just a bit of picky education:  There is no such thing as "Color Postscript".
> The Postscript [tm] Language from Adobe has always had full color support
> from Day 1.

If we take the red book as  the definition of the language at "Day 1", then
at Day 1 the language allowed for setting a current painting color
(setrgbcolor and sethsbcolr), and for querying the interpreter for the
current color setting (currentrgbcolor and currenthsbcolor).  There was
no provision for color in the raster operators.

In 1988 ("Day 1" + 3 years), Adobe published "PostScript Language Color
Operator Definitions" which defined a new color model (cmyk) and the
following new operators:

         setcmykcolor                  currentcmykcolor
         setcolortransfer              currentcolortransfer
         setblackgeneration            currentblackgeneration
         setundercolorremoval          currentundercolorremoval
         setcolorscreen                currentcolorscreen         
         colorimage (in 5 flavors)

It is this version of PostScript [tm] (implemented in version 49), 
which is meant when it is said that Tektronix's Phaser Interpreter is 
compatible with Color PostScript [tm].

-----------------------------------------------------------------

		Jack Slingerland	(503) 685-3985
                 Graphics Printing & Imaging Division
                     Tektronix, Inc  (MS 63-356)
                PO Box 1000;  Wilsonville, Oregon 97070
 jacks@pogo.GPID.TEK.COM                        ...tektronix!pogo!jacks

consult@osiris.UUCP (Unix Consultation Mailbox ) (12/21/88)

In article <627@rocksanne.UUCP> rainero@rocksanne.UUCP (Emil Rainero) writes:
>(Emil's Psychic Forecast for 1989)
>It is interesting to note that even with 24 or 32 bit color images, there is
>no built-in support for compression. (please, no flames about writing it in
>PostScript). With the proliferation of compression/decompression chips,
>I would expect to see further extensions from Adobe.

It seems to me that it would be pretty hard and possibly unrewarding to
design a compression/decompression scheme which would turn ASCII text
into ASCII text (remember that one of the fundamental ideas behind
PostScript is that PS programs are strictly ASCII, thus enhancing
portability) without causing any random breakage in the way the PS
interpreter reads the image.  Perhaps something like "compress the image
then uuencode" would work, but I wouldn't bet on it myself, I'm no Glenn
Reid (and neither is Brian :-).  The final word, anybody?

Phil Kos        uunet!pyrdc!osiris!phil       The Johns Hopkins Hospital

greid@adobe.com (Glenn Reid) (12/22/88)

In article <6505@pogo.GPID.TEK.COM> jacks@pogo.GPID.TEK.COM (Jack Slingerland) writes:
>If we take the red book as  the definition of the language at "Day 1", then
>at Day 1 the language allowed for setting a current painting color
>(setrgbcolor and sethsbcolr), and for querying the interpreter for the
>current color setting (currentrgbcolor and currenthsbcolor).  There was
>no provision for color in the raster operators.
>
>In 1988 ("Day 1" + 3 years), Adobe published "PostScript Language Color
>Operator Definitions" which defined a new color model (cmyk) and the
>following new operators:
>
>         setcmykcolor                  currentcmykcolor
>         setcolortransfer              currentcolortransfer
>         setblackgeneration            currentblackgeneration
>         setundercolorremoval          currentundercolorremoval
>         setcolorscreen                currentcolorscreen         
>         colorimage (in 5 flavors)

This (and other similar messages) is all quite correct.  Perhaps the
original response was a little misleading.  Unfortunately, all of you
are much too sophisticated out there; you don't miss anything :-)

I think that there are several levels of "having color", and it depends
on what you mean.  For example, there are:

	* a color imaging model and the ability to specify color
	* an interpreter having the above operators
	* having a real live color frame buffer and color marking engine, etc.

We at Adobe often get asked the question of whether or not we had to
completely re-engineer the language and the interpreter to support
color.  The answer is no, in the sense that the abstraction of color
and the ability to represent full color in the graphics state and the
painting operations has been there all along.  That is really the hard
part.  Having "setrgbcolor" is just the tip of the iceberg.  It is the
underlying rasterization that has to have a good notion of color built
in.  I (hesitantly) suggest looking at QuickDraw for an example of
post-engineering color into the imaging model.

The recent PostScript language extensions for color added some
capability to express or specify color, which was needed.  We also
plugged in some more memory and made full color frame buffers and
things like that, which you need, and sent the output to a color
marking engine (and did halftoning and lots of other miscellany).

But the spirit of the original message was that the *imaging model* and
the language has contained support for color "since Day 1", which
actually is important, because we haven't had to re-engineer and debug
all the hard stuff in the middle that is concerned with imaging.

I hope this helps clear things up a little bit.  Thanks for all the
responses that correctly point out that we have, in fact, added quite a
bit to support Color.

And therefore I, for one, think it is reasonable to talk about "Color
PostScript".  However, I don't think it is specific enough.  For
example, if you built in "colorimage" and "setcmykcolor" into a
black-and-white printer, in the same way that "setrbgcolor" is there,
would you have a "Color PostScript" printer?  I don't think so.

Holiday cheers....

Glenn Reid
Adobe Systems
Mountain View