Re: MeasureTool Compare question
Re: MeasureTool Compare question
- Subject: Re: MeasureTool Compare question
- From: Matt Nelson <email@hidden>
- Date: Mon, 14 Mar 2005 10:53:18 -0600
Well I do follow you now, however I'm not clear on the precise use of
MeasureTool's Compare then it seems. On another note, I've output a
ECI2002 target to measure my other flexo press. This press usually uses a
laminate for most jobs that is just *slighty* yellow and does tend to a add
an amount of dot gain. Would it be correct to measure and build a profile
from unlaminated material, laminated or an average of both? I'm thinking
laminated, but I'm not as experienced as you guys are.
Thanks,
--
Matt
At 09:11 AM 3/14/2005 -0700, you wrote:
On Mar 14, 2005, at 8:01 AM, Matt Nelson wrote:
I must really not be awake this morning, I'm apparently doing this
wrong. Is not one of things first things one should do after outputting
a test chart, measuring it, building a profile for the device, and then
outputting a corrected chart using the profile created,
is to first compare the uncalibrated output to a known reference, and
then to compare the corrected output to the known reference to see if the
profile worked?
No. A profile doesn't correct output. The profile is merely a snapshot of
actual behavior of the device for which it was made. The theoretical test
I do is converting a Granger Rainbow or Don Hutcheson's RGBXPLORER8. You
can assign your preferred RGB editing space to these targets, then convert
using your new output profile you're testing as the destination. Any
unusual behavior, like massive posterization, is often indicative of bad
measurement data. Moderate posterization could be either bad measurement
data or a less than stellar behaving output device.
The practical test I do is with a series of tagged images, both RGB and
CMYK, representing a wide range of colors and tonality, convert them with
the new profile, and inspect the conversions. It can also be useful to
output the converted files on the actual output device.
I can open the measured chart data in Compare, but which file are you
supposed to use as the reference? I did this before in ProfileMaker 4's
measure tool, but everytime I try to open the reference text file for
the chart, I'm told it "doesn't contain measurement data of CIE type
(error 20718)" so I'm obviously doing it wrong.
Measuretool's Compare function compares device independent values between
two data sets. The reference text file doesn't contain LAB or spectral
values which is why you are getting the error message.
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
-------------------------------------------------------------
Co-author "Real World Color Management, 2nd Edition"
Published by PeachPit Press (ISBN 0-321-26722-2)
--
Matt Nelson, A+, Network +, MCP
Prepress Production Manager
Director of Technology Resources
Nelson Printing Company
Nelson Label Company
Jonesboro, Arkansas
email@hidden
http://www.nelsonprinting.com
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