Re: CMYK spaces used for document creation
Re: CMYK spaces used for document creation
- Subject: Re: CMYK spaces used for document creation
- From: Chris Murphy <email@hidden>
- Date: Tue, 3 Nov 2009 12:34:04 -0500
On Nov 2, 2009, at 3:44 PM, Martin Orpen wrote:
I was using this example to prove that the banding could not be
blamed solely on errors in the profile or problems with the
destination printer.
But you haven't actually done this, because your test is apples and
oranges.
In your Photoshop test, the B2A table of the Argyll produced inkjet
output device profile was used to convert the image. Whereas in your
Argyll devicelink test, you had used Argyll's -G flag which builds a
devicelink using inverted A2B in the destination profile, not the B2A
table. Your test removes the most likely source of the "banding
ugliness" that you're seeing.
So your test has NOT isolated Photoshop conversions as the cause of
the banding problem.
I have converted the 28-ball image test using the devicelink you
supplied, in Photoshop CS4, and end up with essentially identical
values as <http://inside.rgb2cmyk.com/images/Twenty-Eight-Balls_Argyll.tif.zip
> which you call super smooth and sexy.
And I have used sips which uses the Apple CMM, and nothing at all
related to Adobe, to convert the original Bill Atkinson Twenty-Eight
Balls tiff, using the inkjet RGB output device profile that was
embedded in both of your test images. Of course, as a conventional
conversion this means that profile's B2A table is used. The result is
visually very close to that of <http://inside.rgb2cmyk.com/images/Twenty-Eight-Balls_PS.tif.zip
> which you say is bandy and ugly.
So either this ugly banding problem is the result of two major CMMs,
or it's the result of the B2A table in the output device profile,
which was not exist in your devicelink profile due to the use of the
argyll -G option.
Apples and oranges.
Chris Murphy
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