Re: Platoon of doubts
Re: Platoon of doubts
- Subject: Re: Platoon of doubts
- From: Stephen Marsh <email@hidden>
- Date: Tue, 06 Nov 2001 22:15:04 +1100
Adriano Von Markendorf writes:
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Hello !
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Excuse me if I can't express my self
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correctly or look's like a rude way !
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I'm from Brazil and still learning the English.
I will try to keep this is mind when responding - but it's hard when two
native speakers have to converse on technical subjects via text, not to
mention English not being your first written language.
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Well, If you could, give me same advice about a situation here.
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Well I'm trying to profiling a laser printer (CS225) with a Fiery rip (E
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310) if I'm using only photoshop to make my prints - everything it's all
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right - BUT, if I'm trying to print from QuarkXpress 4x (mac) the vector
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objects allways look's like diferent from the image objects, in another
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word's, if I have a retangle (vector object) with 100M / 50Y and the a
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similar retangle with exactly same MY values, but image object, the
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results are very diferent in the final print with the same CMYK values.
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There are some trick to test the color management RIP capabilities? I'm
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missing something?
You mention profiling the laser - and from the problems you describe I
guess that you are using colour management in Quark or the RIP, or both
to apply this profile to the incoming data - so that a colour transform
is applied before print somewhere?
I am just a user - so I can't really comment on the why, how and other
technical stuff. Many others here can.
From your post, it sounds like CMYK is the colour space for input for
output.
Photoshop, Quark and a RIP probably indicate the use of PostScript based
output. Do you use LaserWriter 8, PS Printer or some custom printer
driver for the printer or RIP? I am guessing that you print PostScript
data through the standard LaserWriter 8 PS printer driver.
You CAN do what you request - in it's simplest form, PostScript will
simply pass the given value 100m 50y to the RIP for output. Whether the
file is raster or vector does not matter, the NUMBERS are what matters -
not the profile.
PostScript does not care about input/output profiles - it is designed to
simply pass through unaltered final data.
If you can apply your custom profile in the RIP or somewhere else in the
'back end' (printing to RIP or to a .ps file) - then the profile should
affect the RIPed data, which is would probably be better than attempting
to do everything upstream at the front end.
Basically - if you have a PostScript device and don't use colour
management, the CMYK values in the output will image the same, whether
they are raster or vector.
If you are sending raw numbers to the RIP - then those numbers would
ideally be suited to that device. Thats where the profile comes in, and
an in RIP transform is probably the simplest solution, probably based on
a presumption of the incoming CMYK data (as the numbers require a
description if colour management is being used).
Summary:
(a) For a test, disable colour management in Quark and simply pass raw
CMYK values from imported and native elements direct to the RIP. If a
colour match is required between an imported element and a native
element - they must be based on the same colour model and definition.
When printing to the PostScript RIP, the CMYK print data from Quark
(native and imported objects) will simply pass through unaltered and
image to the RIP as intended.
Thats the beauty of PostScript.
The downside is that once the ink is down and the results are the same
between vector and raster objects - users are unhappy with the overall
colour. This is where managing the colour comes in, and where the
process becomes complex.
(b) If (a) produces a colour match between native and imported objects
(it will when done right), but you may not like the colour result - then
you would need to see where the profile is best implemented into your
workflow.
For example, our large format 6 colour Epson 9000 is driven via an ORIS
colour tuner RIP - which applies the correct profile for media and print
simulation from the incoming CMYK data.
The colour management is handled in the background at the RIP as it
processes the file before print. We need not worry about the front end
of the process, as in printing or colour mangement in Quark.
Hope this helps,
Stephen Marsh.