Validating input profiles
Validating input profiles
- Subject: Validating input profiles
- From: Terry Wyse <email@hidden>
- Date: Tue, 25 Sep 2001 23:17:28 -0400
I'm attempting to devise a method for validating input profiles but I seem
to have run up against a mental roadblock.
My logic goes something like this:
I know what the original measured Lab values are of the testchart I have
captured. I capture this chart in RGB, create the profile and assign this
profile to the image in Photoshop. From here, I should be able to convert
the image to Lab mode and, theoretically, end up with the same Lab values of
the testchart, assuming the testchart is within the color gamut of the
capture device.
Ultimately I would like to use GretagMacbeth's Compare function in the
Measure Tool for comparing the reference testchart to the resulting (Lab)
image. Naturally I can import the reference text file of the testchart but
where I'm getting stumped is in converting my image to a text file WITHOUT
the need to manually create this file by taking samples of the image in
Photoshop.
This is what I've been able to do thus far:
1) I've taken the Lab reference data for the testchart and have
reconstructed a TIFF image of the testchart in Lab mode.
2) I've stripped out the RGB measurements of the captured testchart from the
profile and have reconstructed this as an RGB TIFF image. This is the image
I've used to assign the profile and convert it back to Lab mode.
3) What I'd LIKE to be able to do is take this resulting Lab image and
somehow de-construct it back to a text file with the Lab values. This is the
file I would use to compare to the reference chart and assess the profile.
So I've got a Lab image of the original testchart plus a Lab image of the
captured RGB image of the same chart, assigned the profile and converted to
Lab. I feel like I'm THIS CLOSE to a solution and need a little nudge in the
right direction ("Vanna, I'd like to buy a clue for $200!").
Some of the tools I have at my disposal:
Gretag ProfileMaker
Gretag Measure Tool
Logo ColorLab 2.6
Chromix ColorThink
Looking for a little help...
Terry
_____________________________
Terence L. Wyse
Color Management Specialist
All Systems Integration, Inc.
http://www.allsystems.com
email@hidden
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